The sword refers to the KTH node from the bottom of the offer_ list

Input a linked list, output the last KTH node of the list. 1 find the length of the list 2 take n minus k steps from the starting point

Note:

k >= 1; If k is greater than the list length, NULL is returned;

/** * Definition for singly-linked list. * function ListNode(val) { * this.val = val; * this.next = null; *} * /
/ * * *@param {ListNode} pListHead
 * @param {number} k
 * @return {ListNode}* /
var findKthToTail = function(pListHead, k) {
    // Find the length of the list first
    let cur = pListHead;
    let n = 0;
    while(cur){
        n++;
        cur = cur.next;
    }
    
    // The penultimate KTH node takes n-k steps
    cur = pListHead;
    if(k > n) return null;
    for(let i = 0; i < n - k; i ++){
        cur = cur.next;
    }
    return cur;
};
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