add 19

Author: awesomelike

medium/19-remote-nth-from-list.js

@@ -0,0 +1,36 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @param {number} n
+ * @return {ListNode}
+ */
+ var removeNthFromEnd = function(head, n) {
+  let temp = head;
+  let size = 0;
+  while (temp !== null) {
+    temp = temp.next;
+    size++;
+  }
+  temp = head;
+  let i = 0;
+  while (i <= size - n - 2) {
+    temp = temp.next;
+    i++;
+  }
+  if (size > 1) {
+    if (size - n === 0) {
+      head = head.next;
+    } else {
+      temp.next = temp.next ? temp.next.next : null;      
+    }
+  } else {
+    head = null;
+  }
+  return head;
+};