sovle: remove nth node from end of list

Author: wogha95

remove-nth-node-from-end-of-list/wogha95.js

@@ -0,0 +1,44 @@
+/**
+ * TC: O(N)
+ * SC: O(1)
+ * N: list length
+ */
+
+/**
+ * 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 listLength = 0;
+  let pointer = head;
+
+  while (pointer) {
+    pointer = pointer.next;
+    listLength += 1;
+  }
+
+  // if target of removal is the first node in list
+  if (listLength === n) {
+    return head.next;
+  }
+
+  let nextCount = listLength - n - 1;
+  pointer = head;
+
+  while (nextCount) {
+    pointer = pointer.next;
+    nextCount -= 1;
+  }
+
+  pointer.next = pointer.next.next;
+
+  return head;
+};