TheAlgorithms-C/data_structures/graphs/Graph.c

103 lines
3.2 KiB
C

// Graph ADT
// Adjacency Matrix Representation
#include "Graph.h"
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
typedef struct GraphRep {
int **edges; // adjacency matrix
int nV; // #vertices
int nE; // #edges
} GraphRep;
Graph newGraph(int V) {
assert(V >= 0);
int i;
Graph g = malloc(sizeof(GraphRep));
assert(g != NULL);
g->nV = V;
g->nE = 0;
// allocate memory for each row
g->edges = malloc(V * sizeof(int *));
assert(g->edges != NULL);
// allocate memory for each column and initialise with 0
for (i = 0; i < V; i++) {
g->edges[i] = calloc(V, sizeof(int));
assert(g->edges[i] != NULL);
}
return g;
}
// check if vertex is valid in a graph
bool validV(Graph g, Vertex v) {
return (g != NULL && v >= 0 && v < g->nV);
}
void insertEdge(Graph g, Edge e) {
assert(g != NULL && validV(g,e.v) && validV(g,e.w));
if (!g->edges[e.v][e.w]) { // edge e not in graph
g->edges[e.v][e.w] = 1;
g->edges[e.w][e.v] = 1;
g->nE++;
}
}
void removeEdge(Graph g, Edge e) {
assert(g != NULL && validV(g,e.v) && validV(g,e.w));
if (g->edges[e.v][e.w]) { // edge e in graph
g->edges[e.v][e.w] = 0;
g->edges[e.w][e.v] = 0;
g->nE--;
}
}
bool adjacent(Graph g, Vertex v, Vertex w) {
assert(g != NULL && validV(g,v) && validV(g,w));
return (g->edges[v][w] != 0);
}
void showGraph(Graph g) {
assert(g != NULL);
int i, j;
printf("Number of vertices: %d\n", g->nV);
printf("Number of edges: %d\n", g->nE);
for (i = 0; i < g->nV; i++)
for (j = i+1; j < g->nV; j++)
if (g->edges[i][j])
printf("Edge %d - %d\n", i, j);
}
void freeGraph(Graph g) {
assert(g != NULL);
int i;
for (i = 0; i < g->nV; i++)
free(g->edges[i]);
free(g->edges);
free(g);
}
// By
// .----------------. .----------------. .----------------. .-----------------. .----------------. .----------------.
// | .--------------. || .--------------. || .--------------. || .--------------. | | .--------------. || .--------------. |
// | | _________ | || | _____ _____ | || | __ | || | ____ _____ | | | | ____ ____ | || | ____ | |
// | | | _ _ | | || ||_ _||_ _|| || | / \ | || ||_ \|_ _| | | | | |_ || _| | || | .' `. | |
// | | |_/ | | \_| | || | | | | | | || | / /\ \ | || | | \ | | | | | | | |__| | | || | / .--. \ | |
// | | | | | || | | ' ' | | || | / ____ \ | || | | |\ \| | | | | | | __ | | || | | | | | | |
// | | _| |_ | || | \ `--' / | || | _/ / \ \_ | || | _| |_\ |_ | | | | _| | | |_ | || | \ `--' / | |
// | | |_____| | || | `.__.' | || ||____| |____|| || ||_____|\____| | | | | |____||____| | || | `.____.' | |
// | | | || | | || | | || | | | | | | || | | |
// | '--------------' || '--------------' || '--------------' || '--------------' | | '--------------' || '--------------' |
// '----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
// Email : z5261243@unsw.edu.au
// hhoanhtuann@gmail.com