LeetCode力扣 141. 環形鏈表 Linked List Cycle 題解代碼 JavaScript

問題 https://leetcode-cn.com/problems/valid-palindrome/

練習使用JavaScript解答

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */

/**
 * @param {ListNode} head
 * @return {boolean}
 */
var hasCycle = function(head) {
    var p1 = head, p2 = head;
    while(p1 && p2) {
        p1 = p1.next;
        p2 = p2.next;
        if(!p1)
            return false;
        p1 = p1.next;
        if(p1 === p2)
            return true;
    }
    return false;
};