回文链表

const isPalindrome = function(head) {
    let nodeArr = []

    while(head) {
        nodeArr.push(head.val)
        head = head.next
    }
    
    for(let i = 0, j = nodeArr.length - 1; j >= i; i++, j--)
        if (nodeArr[i] !== nodeArr[j]) return false

    return true
};