First, detect whether a cycle exists using two pointers moving at different speeds.

Linked List Cycle II

medium

Acceptance: 48%

Linked List

Given a linked list that may contain a cycle, identify the node where the cycle begins. If no cycle is present, return null. The cycle entry point is the first node that is revisited when traversing the list.

Examples

Example 1:

Input:head = [1,3,5,7], pos = 1

Output:Node at index 1 (value 3)

Example 2:

Input:head = [2], pos = -1

Output:null

Hints

1234567

import java.util.*;

public class Main {
    public static void main(String[] args) {
        // Write your solution here
    }
}

import java.util.*;

public class Main {
    public static void main(String[] args) {
        // Write your solution here
    }
}

Linked List Cycle II

Examples

Hints

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