topological sort P6
#include <stdio.h>
#include <stdlib.h>
#define MAX_VERTICES 100
// Structure to represent a graph
typedef struct {
int V;
int** adjMatrix;
} Graph;
// Function to create a new graph
Graph* createGraph(int V) {
Graph* graph = (Graph*)malloc(sizeof(Graph));
graph->V = V;
graph->adjMatrix = (int**)calloc(V, sizeof(int*));
for (int i = 0; i < V; i++) {
graph->adjMatrix[i] = (int*)calloc(V, sizeof(int));
}
return graph;
}
// Function to add an edge to the graph
void addEdge(Graph* graph, int src, int dest) {
graph->adjMatrix[src][dest] = 1;
}
// Function to perform topological sorting
void topologicalSort(Graph* graph) {
int V = graph->V;
int inDegree[MAX_VERTICES] = {0};
int queue[MAX_VERTICES], front = 0, rear = -1;
// Calculate in-degree (number of incoming edges) for each vertex
for (int i = 0; i < V; i++) {
for (int j = 0; j < V; j++) {
if (graph->adjMatrix[i][j] == 1) {
inDegree[j]++;
}
}
}
// Enqueue all vertices with in-degree 0
for (int i = 0; i < V; i++) {
if (inDegree[i] == 0) {
queue[++rear] = i;
}
}
printf("Topological ordering of vertices: ");
// Process until the queue is empty
while (front <= rear) {
int vertex = queue[front++];
printf("%d ", vertex);
// Reduce the in-degree of all adjacent vertices
for (int i = 0; i < V; i++) {
if (graph->adjMatrix[vertex][i] == 1 && --inDegree[i] == 0) {
queue[++rear] = i;
}
}
}
printf("\n");
}
// Driver code
int main() {
int V, E;
printf("Enter the number of vertices: ");
scanf("%d", &V);
if (V > MAX_VERTICES) {
printf("Error: Number of vertices exceeds the maximum limit of %d.\n", MAX_VERTICES);
return 1;
}
Graph* graph = createGraph(V);
printf("Enter the number of edges: ");
scanf("%d", &E);
printf("Enter the edges (source vertex, destination vertex):\n");
for (int i = 0, src, dest; i < E; i++) {
scanf("%d %d", &src, &dest);
addEdge(graph, src, dest);
}
topologicalSort(graph);
// Free allocated memory
for (int i = 0; i < V; i++) {
free(graph->adjMatrix[i]);
}
free(graph->adjMatrix);
free(graph);
return 0;
}
Comments
Post a Comment