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#include "graph.h"
#include "vector.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
// Need to declare 'graph_delete' for use in 'graph_new'
void graph_delete(Graph *g);
Graph *graph_new(int n) {
Graph *graph = (Graph *)malloc(sizeof(Graph));
if (!graph)
return NULL;
graph->vertices = (Vertex *)malloc(sizeof(Vertex) * n);
if (!graph->vertices) {
free(graph);
return NULL;
}
graph->num_edges = 0;
graph->num_vertices = n;
for (int i = 0; i < n; i++) {
graph->vertices[i].id = i;
graph->vertices[i].out_neighbours = vector_new();
graph->vertices[i].in_neighbours = vector_new();
// if allocation for the linked lists failed
if (!graph->vertices[i].out_neighbours
|| !graph->vertices[i].in_neighbours) {
graph_delete(graph);
return NULL;
}
}
return graph;
}
void graph_add_edge(Graph *g, int i, int j) {
vector_push(g->vertices[i].out_neighbours, &g->vertices[j]);
vector_push(g->vertices[j].in_neighbours, &g->vertices[i]);
g->num_edges++;
}
Graph *graph_read(const char *filename) {
FILE *file = fopen(filename, "r");
if (!file)
return NULL;
char line[1024];
if (!fgets(line, sizeof(line), file)) {
fclose(file);
return NULL;
}
int n = atoi(line);
if (n <= 0) {
fclose(file);
return NULL;
}
Graph *g = graph_new(n);
if (!g) {
fclose(file);
return NULL;
}
for (int i = 0; i < n; i++) {
if (!fgets(line, sizeof(line), file)) {
fprintf(stderr, "Error: Could not read row %d\n", i);
fclose(file);
return g;
}
int j = 0;
int col = 0;
while (col < n && line[j] != '\0' && line[j] != '\n') {
if (line[j] == '1') {
graph_add_edge(g, i, col);
col++;
} else if (line[j] == '0') {
col++;
}
// skip any other characters
j++;
}
}
fclose(file);
return g;
}
void graph_print(Graph *g) {
fprintf(stdout, "Number of vertices: %d\n", g->num_vertices);
fprintf(stdout, "Number of edges: %d\n", g->num_edges);
}
void graph_delete(Graph *g) {
for (int i = 0; i < g->num_vertices; i++) {
vector_delete(g->vertices[i].in_neighbours);
vector_delete(g->vertices[i].out_neighbours);
}
free(g->vertices);
free(g);
}
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