دانلود سورس تشخیص دور گراف در سی پلاس پلاس

Graph G1 contains cycle
Graph G2 doesn't contain cycle

// A recursive function that uses visited[] and parent to detect
// cycle in subgraph reachable from vertex v.
bool Graph::isCyclicUtil(int v, bool visited[], int parent) {
// Mark the current node as visited
visited[v] = true;
// Recur for all the vertices adjacent to this vertex
list<int>::iterator i;
for (i = adj[v].begin(); i != adj[v].end(); ++i) {
// If an adjacent is not visited, then recur for that adjacent
if (!visited[*i]) {
if (isCyclicUtil(*i, visited, v))
return true;
}
// If an adjacent is visited and not parent of current vertex,
// then there is a cycle.
else if (*i != parent)
return true;
}
return false;
}
// Returns true if the graph contains a cycle, else false.
bool Graph::isCyclic() {
// Mark all the vertices as not visited and not part of recursion
// stack
bool *visited = new bool[V];
for (int i = 0; i < V; i++)
visited[i] = false;
// Call the recursive helper function to detect cycle in different
// DFS trees
for (int u = 0; u < V; u++)
if (!visited[u]) // Don't recur for u if it is already visited
if (isCyclicUtil(u, visited, -1))
return true;
return false;
}