19

Author: LeuisKen

19.js

@@ -0,0 +1,33 @@
+/**
+ * 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,
+		pos = head,
+		count = 0;
+	while(temp.next !== null){
+		temp = temp.next;
+		count++;
+		if(count === n) break;
+	}
+	if(count !== n){
+		head = head.next;
+		return head;
+	}
+	while(temp.next !== null){
+		temp = temp.next;
+		pos = pos.next;
+	}
+	if(pos.next === null) return null;
+	pos.next = pos.next.next;
+	return head;
+};