题解 | #链表中环的入口结点#

package suanfa.list;

import java.util.HashSet;
import java.util.Set;

/**

• 链表中环的入口结点

• /
  public class EntryNodeOfLoop {

  public ListNode EntryNodeOfLoop(ListNode pHead) {

    Set<ListNode> set = new HashSet<>();
    while (pHead != null) {
        if (set.contains(pHead)) {
            return pHead;
        } else {
            set.add(pHead);
        }
        pHead = pHead.next;
    }
    return null;

  }

  static class ListNode {

    int val;
    ListNode next;

  }
  }