Algorithm——Remove Nth Node From End of List

Remove Nth Node From End of List

Given a linked list, remove the n-th node from the end of list and return its head.

Example:

Given linked list: 1->2->3->4->5, and n = 2.

After removing the second node from the end, the linked list becomes 1->2->3->5.

 

Note:

Given n will always be valid.

Ans:

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} head
 * @param {number} n
 * @return {ListNode}
 */
var removeNthFromEnd = function(head, n) {
    var temp = head;
    for (let i = 0; i < n; i++) {
        temp = temp.next;
    }
    
    if(!temp) return head.next; // n equals list.length
    
    var cur = head;
    while(temp.next) {
        temp = temp.next;
        cur = cur.next;
    }
    
    cur.next = cur.next.next;
    
    return head;
};

 

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