Add week 7 solutions : removeNthNodeFromEndOfList

Author: yolophg

remove-nth-node-from-end-of-list/yolophg.js

@@ -0,0 +1,32 @@
+// Time Complexity: O(n)
+// Space Complexity: O(1)
+
+var removeNthFromEnd = function (head, n) {
+  // calculate the length of the linked list.
+  let length = 0;
+  let current = head;
+  while (current !== null) {
+    length++;
+    current = current.next;
+  }
+
+  // determine the position to remove from the start.
+  let removeIndex = length - n;
+
+  // if the node to be removed is the head, return the next node.
+  if (removeIndex === 0) {
+    return head.next;
+  }
+
+  // traverse to the node just before the node to be removed.
+  current = head;
+  for (let i = 0; i < removeIndex - 1; i++) {
+    current = current.next;
+  }
+
+  // remove the nth node from the end.
+  current.next = current.next.next;
+
+  // return the modified list.
+  return head;
+};