Merge pull request #72 from MacBox7/bucket-sort

Thanks for contributing

sorting/BucketSort.c

@@ -0,0 +1,175 @@
+/*
+* Algorithm : Bucket Sort
+* Time-Complexity : O(n)
+*/
+#include <stdio.h>
+#include <stdlib.h>
+
+#define NARRAY 8  /* array size */
+#define NBUCKET 5 /* bucket size */
+#define INTERVAL 10 /* bucket range */
+
+struct Node 
+{ 
+	int data;  
+	struct Node *next; 
+};
+
+void BucketSort(int arr[]);
+struct Node *InsertionSort(struct Node *list);
+void print(int arr[]);
+void printBuckets(struct Node *list);
+int getBucketIndex(int value);
+
+void BucketSort(int arr[])
+{	
+	int i,j;
+	struct Node **buckets;  
+
+	/* allocate memory for array of pointers to the buckets */
+	buckets = (struct Node **)malloc(sizeof(struct Node*) * NBUCKET); 
+
+	/* initialize pointers to the buckets */
+	for(i = 0; i < NBUCKET;++i) {  
+		buckets[i] = NULL;
+	}
+
+	/* put items into the buckets */
+	for(i = 0; i < NARRAY; ++i) {	
+		struct Node *current;
+		int pos = getBucketIndex(arr[i]);
+		current = (struct Node *) malloc(sizeof(struct Node));
+		current->data = arr[i]; 
+		current->next = buckets[pos];  
+		buckets[pos] = current;
+	}
+
+	/* check what's in each bucket */
+	for(i = 0; i < NBUCKET; i++) {
+		printf("Bucket[\"%d\"] : ", i);
+	        printBuckets(buckets[i]);
+		printf("\n");
+	}
+
+	/* sorting bucket using Insertion Sort */
+	for(i = 0; i < NBUCKET; ++i) {  
+		buckets[i] = InsertionSort(buckets[i]); 
+	}
+
+	/* check what's in each bucket */
+    printf("--------------\n");
+    printf("Buckets after sorted\n");
+	for(i = 0; i < NBUCKET; i++) {
+		printf("Bucket[\"%d\"] : ", i);
+	        printBuckets(buckets[i]);
+		printf("\n");
+	}
+
+	/* put items back to original array */
+	for(j =0, i = 0; i < NBUCKET; ++i) {	
+		struct Node *node;
+		node = buckets[i];
+		while(node) {
+			arr[j++] = node->data;
+			node = node->next;
+		}
+	}
+	
+	/* free memory */
+	for(i = 0; i < NBUCKET;++i) {	
+		struct Node *node;
+		node = buckets[i];
+		while(node) {
+			struct Node *tmp;
+			tmp = node; 
+			node = node->next; 
+			free(tmp);
+		}
+	}
+	free(buckets); 
+	return;
+}
+
+/* Insertion Sort */
+struct Node *InsertionSort(struct Node *list)
+{	
+	struct Node *k,*nodeList;
+	/* need at least two items to sort */
+	if(list == 0 || list->next == 0) { 
+		return list; 
+	}
+	
+	nodeList = list; 
+	k = list->next; 
+	nodeList->next = 0; /* 1st node is new list */
+	while(k != 0) {	
+		struct Node *ptr;
+		/* check if insert before first */
+		if(nodeList->data > k->data)  { 
+			struct Node *tmp;
+			tmp = k;  
+			k = k->next; 
+			tmp->next = nodeList;
+			nodeList = tmp; 
+			continue;
+		}
+
+		for(ptr = nodeList; ptr->next != 0; ptr = ptr->next) {
+			if(ptr->next->data > k->data) break;
+		}
+
+		if(ptr->next!=0){  
+			struct Node *tmp;
+			tmp = k;  
+			k = k->next; 
+			tmp->next = ptr->next;
+			ptr->next = tmp; 
+			continue;
+		}
+		else{
+			ptr->next = k;  
+			k = k->next;  
+			ptr->next->next = 0; 
+			continue;
+		}
+	}
+	return nodeList;
+}
+
+int getBucketIndex(int value)
+{
+	return value/INTERVAL;
+}
+
+void print(int ar[])
+{	
+	int i;
+	for(i = 0; i < NARRAY; ++i) { 
+		printf("%d ", ar[i]);
+	}
+	printf("\n");
+}
+
+void printBuckets(struct Node *list)
+{
+	struct Node *cur = list;
+	while(cur) {
+		printf("%d ", cur->data);
+		cur = cur->next;
+	}
+}
+
+int main(void)
+{	
+	int array[NARRAY] = {29,25,-1,49,9,37,21,43};
+
+    printf("Initial array\n");
+    print(array);
+    printf("------------\n");
+
+	BucketSort(array); 
+    printf("------------\n");
+	printf("Sorted array\n");
+	print(array); 
+	return 0;
+}