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 fast = pHead, slow = pHead;
    if (!fast || k===0)  return null;
    for (let i=0;i<k-1;i++){
        if (fast.next === null) return null;
        fast = fast.next;
    }
    while(fast.next){
        fast = fast.next;
        slow = slow.next;
    }
    return slow;
}
module.exports = {
    FindKthToTail : FindKthToTail
};