题解 | #链表中倒数最后k个结点#

/*
 * 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 pHead ListNode类 
 * @param k int整型 
 * @return ListNode类
 */
function FindKthToTail( pHead ,  k ) {
    // write code here
    let p1 = pHead
    let p2 = pHead
    let sum = 0
    let current = 0
    while(p1) {
        sum += 1
        p1 = p1.next
    }
    while(p2) {
        current += 1
        if(current === sum-k+1) {
            return p2
        }
        p2 = p2.next
    }
    return null
}
module.exports = {
    FindKthToTail : FindKthToTail
};