How do I detect cycles in a graph using C programming?

How do I detect cycles in a graph using C programming?

To detect cycles in a graph using C, you can use Depth First Search (DFS) or Union-Find algorithms. Which one would you like to explore?

Can you explain how to implement DFS for cycle detection?

Sure! In DFS, you can keep track of visited nodes and the recursion stack. If you encounter a node that is already in the recursion stack, a cycle exists.

What does the code look like for that?

Here's a simple implementation:

#include <stdio.h>
#include <stdlib.h>

#define MAX 100

int graph[MAX][MAX], visited[MAX], recStack[MAX];

int isCyclicUtil(int v, int n) {
    visited[v] = 1;
    recStack[v] = 1;

    for (int i = 0; i < n; i++) {
        if (graph[v][i]) {
            if (!visited[i] && isCyclicUtil(i, n))
                return 1;
            else if (recStack[i])
                return 1;
        }
    }
    recStack[v] = 0;
    return 0;
}

int isCyclic(int n) {
    for (int i = 0; i < n; i++) {
        if (!visited[i]) {
            if (isCyclicUtil(i, n))
                return 1;
        }
    }
    return 0;
}

Would you like to know more about how this code works?

Yes, please explain the key parts of the code.

The key parts include:

1. visited[]: Tracks if a node has been visited.
2. recStack[]: Keeps track of nodes in the current path of DFS.
3. isCyclicUtil(): Recursively checks for cycles by exploring adjacent nodes and checking the recursion stack.