mirror of
https://github.com/TheAlgorithms/C
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778f317e82
* Rename redblacktree.c to red_black_tree.c
* updating DIRECTORY.md
* add renaming avl.c and ascendingpriorityqueue.c
* updating DIRECTORY.md
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
798 lines
21 KiB
C
798 lines
21 KiB
C
#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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typedef struct node
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{
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int val;
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struct node *par;
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struct node *left;
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struct node *right;
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int color;
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} Node;
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// Create a new node
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Node *newNode(int val, Node *par)
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{
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Node *create = (Node *)(malloc(sizeof(Node)));
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create->val = val;
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create->par = par;
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create->left = NULL;
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create->right = NULL;
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create->color = 1;
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}
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// Check if the node is the leaf
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int isLeaf(Node *n)
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{
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if (n->left == NULL && n->right == NULL)
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{
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return 1;
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}
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return 0;
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}
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// Left Rotate
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Node *leftRotate(Node *node)
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{
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Node *parent = node->par;
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Node *grandParent = parent->par;
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parent->right = node->left;
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if (node->left != NULL)
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{
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node->left->par = parent;
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}
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node->par = grandParent;
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parent->par = node;
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node->left = parent;
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if (grandParent != NULL)
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{
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if (grandParent->right == parent)
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{
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grandParent->right = node;
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}
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else
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{
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grandParent->left = node;
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}
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}
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return node;
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}
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// Right Rotate
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Node *rightRotate(Node *node)
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{
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Node *parent = node->par;
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Node *grandParent = parent->par;
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parent->left = node->right;
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if (node->right != NULL)
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{
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node->right->par = parent;
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}
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node->par = grandParent;
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parent->par = node;
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node->right = parent;
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if (grandParent != NULL)
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{
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if (grandParent->right == parent)
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{
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grandParent->right = node;
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}
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else
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{
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grandParent->left = node;
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}
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}
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return node;
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}
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// Check the node after the insertion step
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void checkNode(Node *node)
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{
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// If the node is the root
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if (node == NULL || node->par == NULL)
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{
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return;
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}
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Node *child = node;
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// If it is a black node or its parent is a black node
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if (node->color == 0 || (node->par)->color == 0)
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{
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// Dont Do Anything
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return;
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}
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// Both parent and child are red
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// Check For Uncle
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Node *parent = node->par;
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Node *grandParent = parent->par;
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// If grandParent is NULL, then parent is the root.
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// Just make the root black.
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if (grandParent == NULL)
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{
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parent->color = 0;
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return;
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}
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// If both the children of the grandParent are red
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if (grandParent->right != NULL && (grandParent->right)->color == 1 &&
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grandParent->left != NULL && (grandParent->left)->color == 1)
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{
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// Make the grandParent red and both of its children black
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(grandParent->right)->color = 0;
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(grandParent->left)->color = 0;
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grandParent->color = 1;
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return;
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}
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else
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{
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// The only option left is rotation.
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Node *greatGrandParent = grandParent->par;
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// Right Case
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if (grandParent->right == parent)
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{
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// Right Right Case
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if (parent->right == node)
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{
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grandParent->right = parent->left;
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if (parent->left != NULL)
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{
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(parent->left)->par = grandParent;
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}
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parent->left = grandParent;
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grandParent->par = parent;
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// Attach to existing Tree;
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parent->par = greatGrandParent;
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if (greatGrandParent != NULL)
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{
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if (greatGrandParent->left != NULL &&
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greatGrandParent->left == grandParent)
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{
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greatGrandParent->left = parent;
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}
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else
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{
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greatGrandParent->right = parent;
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}
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}
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// Change the colors
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parent->color = 0;
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grandParent->color = 1;
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}
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else
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{ // Right Left Case
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// First step -> Parent Child Rotation
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parent->left = child->right;
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if (child->right != NULL)
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{
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(child->right)->par = parent;
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}
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child->right = parent;
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parent->par = child;
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// Second step -> Child and GrandParent Rotation
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grandParent->right = child->left;
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if (child->left != NULL)
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{
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(child->left)->par = grandParent;
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}
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child->left = grandParent;
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grandParent->par = child;
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// Attach to the existing tree
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child->par = greatGrandParent;
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if (greatGrandParent != NULL)
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{
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if (greatGrandParent->left != NULL &&
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greatGrandParent->left == grandParent)
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{
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greatGrandParent->left = child;
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}
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else
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{
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greatGrandParent->right = child;
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}
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}
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// Change The Colors
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child->color = 0;
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grandParent->color = 1;
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}
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}
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else
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{ // Left Case
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// Left Left Case
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if (parent->left == node)
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{
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grandParent->left = parent->right;
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if (parent->right != NULL)
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{
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(parent->right)->par = grandParent;
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}
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parent->right = grandParent;
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grandParent->par = parent;
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// Attach to existing Tree;
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parent->par = greatGrandParent;
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if (greatGrandParent != NULL)
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{
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if (greatGrandParent->left != NULL &&
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greatGrandParent->left == grandParent)
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{
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greatGrandParent->left = parent;
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}
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else
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{
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greatGrandParent->right = parent;
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}
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}
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// Change the colors
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parent->color = 0;
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grandParent->color = 1;
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}
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else
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{ // Left Right Case
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// First step -> Parent Child Rotation
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parent->right = child->left;
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if (child->left != NULL)
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{
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(child->left)->par = parent;
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}
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child->left = parent;
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parent->par = child;
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// Second step -> Child and GrandParent Rotation
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grandParent->left = child->right;
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if (child->right != NULL)
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{
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(child->right)->par = grandParent;
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}
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child->right = grandParent;
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grandParent->par = child;
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// Attach to the existing tree
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child->par = greatGrandParent;
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if (greatGrandParent != NULL)
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{
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if (greatGrandParent->left != NULL &&
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greatGrandParent->left == grandParent)
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{
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greatGrandParent->left = child;
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}
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else
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{
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greatGrandParent->right = child;
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}
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}
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// Change The Colors
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child->color = 0;
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grandParent->color = 1;
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}
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}
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}
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}
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// To insert a node in the existing tree
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void insertNode(int val, Node **root)
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{
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Node *buffRoot = *root;
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while (buffRoot)
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{
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if (buffRoot->val > val)
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{
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// Go left
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if (buffRoot->left != NULL)
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{
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buffRoot = buffRoot->left;
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}
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else
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{
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// Insert The Node
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Node *toInsert = newNode(val, buffRoot);
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buffRoot->left = toInsert;
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buffRoot = toInsert;
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// Check For Double Red Problems
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break;
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}
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}
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else
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{
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// Go right
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if (buffRoot->right != NULL)
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{
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buffRoot = buffRoot->right;
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}
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else
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{
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// Insert The Node
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Node *toInsert = newNode(val, buffRoot);
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buffRoot->right = toInsert;
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buffRoot = toInsert;
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// Check For Double Red Problems
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break;
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}
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}
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}
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while (buffRoot != *root)
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{
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checkNode(buffRoot);
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if (buffRoot->par == NULL)
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{
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*root = buffRoot;
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break;
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}
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buffRoot = buffRoot->par;
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if (buffRoot == *root)
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{
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buffRoot->color = 0;
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}
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}
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}
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void checkForCase2(Node *toDelete, int delete, int fromDirection, Node **root)
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{
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if (toDelete == (*root))
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{
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(*root)->color = 0;
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return;
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}
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if (!delete &&toDelete->color == 1)
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{
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if (!fromDirection)
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{
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if (toDelete->right != NULL)
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{
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toDelete->right->color = 1;
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}
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}
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else
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{
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if (toDelete->left != NULL)
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{
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toDelete->left->color = 1;
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}
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}
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toDelete->color = 0;
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return;
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}
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// Get the sibling for further inspection
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Node *sibling;
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Node *parent = toDelete->par;
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int locateChild = 0; // 0 if toDeleted is left of its parent else 1
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if (parent->right == toDelete)
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{
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sibling = parent->left;
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locateChild = 1;
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}
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else
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{
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sibling = parent->right;
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}
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// Case 2.1. i.e. if the any children of the sibling is red
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if ((sibling->right != NULL && sibling->right->color == 1) ||
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(sibling->left != NULL && sibling->left->color == 1))
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{
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if (sibling->right != NULL && sibling->right->color == 1)
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{
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// Sibling is left and child is right. i.e. LEFT RIGHT ROTATION
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if (locateChild == 1)
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{
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int parColor = parent->color;
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// Step 1: Left rotate sibling
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sibling = leftRotate(sibling->right);
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// Step 2: Right rotate updated sibling
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parent = rightRotate(sibling);
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// Check if the root is rotated
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if (parent->par == NULL)
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{
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*root = parent;
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}
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// Step 3: Update the colors
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parent->color = parColor;
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parent->left->color = 0;
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parent->right->color = 0;
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// Delete the node (present at parent->right->right)
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if (delete)
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{
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if (toDelete->left != NULL)
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{
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toDelete->left->par = parent->right;
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}
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parent->right->right = toDelete->left;
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free(toDelete);
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}
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}
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else
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{ // Sibling is right and child is also right. i.e. LEFT LEFT
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// ROTATION
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int parColor = parent->color;
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// Left Rotate the sibling
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parent = leftRotate(sibling);
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// Check if the root is rotated
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if (parent->par == NULL)
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{
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*root = parent;
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}
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// Update Colors
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parent->color = parColor;
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parent->left->color = 0;
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parent->right->color = 0;
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// Delete the node (present at parent->left->left)
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if (delete)
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{
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if (toDelete->right != NULL)
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{
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toDelete->right->par = parent->left;
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}
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parent->left->left = toDelete->left;
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free(toDelete);
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}
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}
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}
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else
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{
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// Sibling is right and child is left. i.e. RIGHT LEFT ROTATION
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if (locateChild == 0)
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{
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int parColor = parent->color;
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// Step 1: Right rotate sibling
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sibling = rightRotate(sibling->left);
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// printf("%d - reached\n", sibling->val);
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// return;
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// Step 2: Left rotate updated sibling
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parent = leftRotate(sibling);
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// Check if the root is rotated
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if (parent->par == NULL)
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{
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*root = parent;
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}
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// Step 3: Update the colors
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parent->color = parColor;
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parent->left->color = 0;
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parent->right->color = 0;
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// Delete the node (present at parent->left->left)
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if (delete)
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{
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if (toDelete->right != NULL)
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{
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toDelete->right->par = parent->left;
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}
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parent->left->left = toDelete->right;
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free(toDelete);
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}
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}
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else
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{ // Sibling is left and child is also left. i.e. RIGHT RIGHT
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// ROTATION
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int parColor = parent->color;
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// Right Rotate the sibling
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parent = rightRotate(sibling);
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// Check if the root is rotated
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if (parent->par == NULL)
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{
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*root = parent;
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}
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// Update Colors
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parent->color = parColor;
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parent->left->color = 0;
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parent->right->color = 0;
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// Delete the node (present at parent->right->right)
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if (delete)
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{
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if (toDelete->left != NULL)
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{
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toDelete->left->par = parent->right;
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}
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parent->right->right = toDelete->left;
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free(toDelete);
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}
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}
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}
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}
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else if (sibling->color == 0)
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{ // Make the sibling red and recur for its parent
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// Recolor the sibling
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sibling->color = 1;
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// Delete if necessary
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if (delete)
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{
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if (locateChild)
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{
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toDelete->par->right = toDelete->left;
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if (toDelete->left != NULL)
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{
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toDelete->left->par = toDelete->par;
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}
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}
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else
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{
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toDelete->par->left = toDelete->right;
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if (toDelete->right != NULL)
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{
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toDelete->right->par = toDelete->par;
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}
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}
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}
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checkForCase2(parent, 0, locateChild, root);
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}
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else
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{ // Bring the sibling on top and apply 2.1 or 2.2 accordingly
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if (locateChild)
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{ // Right Rotate
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toDelete->par->right = toDelete->left;
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if (toDelete->left != NULL)
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{
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toDelete->left->par = toDelete->par;
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}
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parent = rightRotate(sibling);
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// Check if the root is rotated
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if (parent->par == NULL)
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{
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*root = parent;
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}
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parent->color = 0;
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parent->right->color = 1;
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checkForCase2(parent->right, 0, 1, root);
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}
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else
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{ // Left Rotate
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toDelete->par->left = toDelete->right;
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if (toDelete->right != NULL)
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{
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toDelete->right->par = toDelete->par;
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}
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parent = leftRotate(sibling);
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// Check if the root is rotated
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if (parent->par == NULL)
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{
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*root = parent;
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}
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printf("\nroot - %d - %d\n", parent->val, parent->left->val);
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parent->color = 0;
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parent->left->color = 1;
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checkForCase2(parent->left, 0, 0, root);
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}
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}
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}
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// To delete a node from the tree
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void deleteNode(int val, Node **root)
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{
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Node *buffRoot = *root;
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// Search for the element in the tree
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while (1)
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{
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if (val == buffRoot->val)
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{
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// Node Found
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break;
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}
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if (val > buffRoot->val)
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{
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if (buffRoot->right != NULL)
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{
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buffRoot = buffRoot->right;
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}
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else
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{
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printf("Node Not Found!!!");
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return;
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}
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}
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else
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{
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if (buffRoot->left != NULL)
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{
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buffRoot = buffRoot->left;
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}
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else
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{
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printf("Node Not Found!!!");
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return;
|
|
}
|
|
}
|
|
}
|
|
|
|
Node *toDelete = buffRoot;
|
|
|
|
// Look for the leftmost of right node or right most of left node
|
|
if (toDelete->left != NULL)
|
|
{
|
|
toDelete = toDelete->left;
|
|
while (toDelete->right != NULL)
|
|
{
|
|
toDelete = toDelete->right;
|
|
}
|
|
}
|
|
else if (toDelete->right != NULL)
|
|
{
|
|
toDelete = toDelete->right;
|
|
while (toDelete->left != NULL)
|
|
{
|
|
toDelete = toDelete->left;
|
|
}
|
|
}
|
|
|
|
if (toDelete == *root)
|
|
{
|
|
*root = NULL;
|
|
return;
|
|
}
|
|
|
|
// Swap the values
|
|
buffRoot->val = toDelete->val;
|
|
toDelete->val = val;
|
|
|
|
// Checking for case 1
|
|
if (toDelete->color == 1 ||
|
|
(toDelete->left != NULL && toDelete->left->color == 1) ||
|
|
(toDelete->right != NULL && toDelete->right->color == 1))
|
|
{
|
|
// if it is a leaf
|
|
if (toDelete->left == NULL && toDelete->right == NULL)
|
|
{
|
|
// Delete instantly
|
|
if (toDelete->par->left == toDelete)
|
|
{
|
|
toDelete->par->left = NULL;
|
|
}
|
|
else
|
|
{
|
|
toDelete->par->right = NULL;
|
|
}
|
|
}
|
|
else
|
|
{ // else its child should be red
|
|
|
|
// Check for the exitstence of left node
|
|
if (toDelete->left != NULL)
|
|
{
|
|
// The node should be right to its parent
|
|
toDelete->par->right = toDelete->left;
|
|
toDelete->left->par = toDelete->par;
|
|
toDelete->left->color = 1;
|
|
}
|
|
else
|
|
{ // else the right node should be red
|
|
toDelete->par->left = toDelete->right;
|
|
toDelete->right->par = toDelete->par;
|
|
toDelete->right->color = 1;
|
|
}
|
|
}
|
|
|
|
// Remove the node from memory
|
|
free(toDelete);
|
|
}
|
|
else
|
|
{ // Case 2
|
|
checkForCase2(toDelete, 1, ((toDelete->par->right == toDelete)), root);
|
|
}
|
|
}
|
|
|
|
void printInorder(Node *root)
|
|
{
|
|
if (root != NULL)
|
|
{
|
|
printInorder(root->left);
|
|
printf("%d c-%d ", root->val, root->color);
|
|
printInorder(root->right);
|
|
}
|
|
}
|
|
|
|
void checkBlack(Node *temp, int c)
|
|
{
|
|
if (temp == NULL)
|
|
{
|
|
printf("%d ", c);
|
|
return;
|
|
}
|
|
if (temp->color == 0)
|
|
{
|
|
c++;
|
|
}
|
|
checkBlack(temp->left, c);
|
|
checkBlack(temp->right, c);
|
|
}
|
|
|
|
int main()
|
|
{
|
|
Node *root = NULL;
|
|
int scanValue, choice = 1;
|
|
printf(
|
|
"1 - Input\n2 - Delete\n3 - Inorder Traversel\n0 - Quit\n\nPlease "
|
|
"Enter the Choice - ");
|
|
scanf("%d", &choice);
|
|
while (choice)
|
|
{
|
|
switch (choice)
|
|
{
|
|
case 1:
|
|
printf("\n\nPlease Enter A Value to insert - ");
|
|
scanf("%d", &scanValue);
|
|
if (root == NULL)
|
|
{
|
|
root = newNode(scanValue, NULL);
|
|
root->color = 0;
|
|
}
|
|
else
|
|
{
|
|
insertNode(scanValue, &root);
|
|
}
|
|
printf("\nSuccessfully Inserted %d in the tree\n\n", scanValue);
|
|
break;
|
|
case 2:
|
|
printf("\n\nPlease Enter A Value to Delete - ");
|
|
scanf("%d", &scanValue);
|
|
deleteNode(scanValue, &root);
|
|
printf("\nSuccessfully Inserted %d in the tree\n\n", scanValue);
|
|
break;
|
|
case 3:
|
|
printf("\nInorder Traversel - ");
|
|
printInorder(root);
|
|
printf("\n\n");
|
|
// checkBlack(root,0);
|
|
// printf("\n");
|
|
break;
|
|
default:
|
|
if (root != NULL)
|
|
{
|
|
printf("Root - %d\n", root->val);
|
|
}
|
|
}
|
|
printf(
|
|
"1 - Input\n2 - Delete\n3 - Inorder Traversel\n0 - "
|
|
"Quit\n\nPlease Enter the Choice - ");
|
|
scanf("%d", &choice);
|
|
}
|
|
}
|
|
|
|
// 32 12 50 53 1 2 3 4 5 6 7 8 9
|