Remove nth node from end of list

Author: eunhwa99

remove-nth-node-from-end-of-list/eunhwa99.kt

@@ -0,0 +1,31 @@
+package leetcode_study
+
+class ListNode(var `val`: Int) {
+    var next: ListNode? = null
+}
+
+// 힌트 참고
+// Time Complexity: O(L) where L is the length of the linked list
+// Space Complexity: O(1) since we are using only a constant amount of space
+class Solution {
+    fun removeNthFromEnd(head: ListNode?, n: Int): ListNode? {
+        var left = head
+        var right = head
+        var step = n
+        while (step-- > 0) {
+            right = right?.next
+        }
+        if (right == null) {
+            return head?.next // n이 리스트의 길이와 같을 때, 즉 첫 번째 노드를 제거해야 하는 경우
+        }
+        while (right?.next != null) {
+            left = left?.next
+            right = right.next
+        }
+
+        left?.next = left?.next?.next
+        return head
+    }
+}
+
+