题解 | #链表中环的入口结点# 自定义Hash

import java.util.*;
/*
 public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}
*/
public class Solution {
    // 计算哈希值
    public int computedHash(ListNode node) {
        int hash = 0;
        if (node != null) {
            hash += (node.val << 14);
        }
        if (node.next != null) {
            hash  = node.next.val << 7 ^ hash;
        }
        System.out.println(node.val);
        System.out.println(hash);
        return hash;
    }

    public ListNode EntryNodeOfLoop(ListNode pHead) {
        HashMap<Integer, ListNode> hmap = new HashMap<>();
        while (pHead != null) {
            if (hmap.containsKey(computedHash(pHead))) {
                return hmap.get(computedHash(pHead));
            }
            hmap.put(computedHash(pHead), pHead);
            pHead = pHead.next;
        }
        return null;
    }
}

有更好的哈希计算方法，我这里只是单纯为了好写，能跑通就是成功！