题解 | #牛群编号的回文顺序#

/*
 * function ListNode(x){
 *   this.val = x;
 *   this.next = null;
 * }
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param head ListNode类 
 * @return bool布尔型
 */
function isPalindrome(head) {
    // write code here
    let curr = head
    let arr = []
    let length = 0

    while (curr) {
        length++
        curr = curr.next
    }

    let mid = Math.floor(length / 2)
    curr = head

    for (let i = 0; i < mid; i++) {
        arr.push(curr.val)
        curr = curr.next
    }   

    if(length % 2 !== 0){
        curr = curr.next
    }

    while(curr){
        if(curr.val !== arr.pop()){
            return false
        }
        curr = curr.next
    }

    return true
}   
module.exports = {
    isPalindrome: isPalindrome
};