1packageleetcode;23publicclassDetectCycle {4publicListNode detectCycle(ListNode head) {5ListNode s=head;6ListNode f=head;7while(f!=null&&f.next!=null){8s=s.next;9f=f.next.next;10if(s==f){11break;12}13}14if(f==null||f.next==null)15returnnull;16s=head;17while(s!=f){18s=s.nex...
then there is a cycle in the tree. The edge that connects current vertex to the vertex in the recursion stack is back edge. We have used recStack[] array to keep track of vertices in the recursion
write a function to check whether the graph contains a cycle. if edges = [0, 1], [1, 2], [0, 2]], it means 0 -> 1, 1 ->2, 0 -> 2. edges[i is parent, edgesiis child.
Given a 2D array of charactersgridof sizem x n, you need to find if there exists any cycle consisting of the same value ingrid. A cycle is a path of length 4 or more in the grid that starts and ends at the same cell. From a given cell, you can move to one of the cells adjac...
Detect Cycle in a Directed Graph https://www.geeksforgeeks.org/detect-cycle-in-a-graph/ 有向图里的环必须是 a->b b->c c->a 类似这种的环(包括自环)。 这学期刚上过算法,dfs遍历图会得到dfs tree(如果不是连通图就是forest),并提到了back edge的概念。如果dfs遍历图的时候,有back edge产生,那...