2021年3月31日 链表中倒数第K个节点

// 解法一
function fo(head,n){
    let list = head;
  let len = 0;
    while(list.next != null){
        ++len;
        list = list.next;
  }
  let i = len - n;
  while(list.next != null){
        ++len;
    if(len == i){
        return list;
    } else {
        list = list.next;
    }
  }
}
// 解法二
function fo(head,n){
    let list1 = head;
  let list2 = head;
    while(n==0){
        n--;
        list1 = list1.next;
  }
 while(list1.next != null){
           list1 = list1.next;
          list2 = list2.next;
 }
}