reverse-linked-list solution

Author: lhc0506

reverse-linked-list/lhc0506.js

@@ -0,0 +1,28 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @return {ListNode}
+ */
+var reverseList = function(head) {
+  let prevNode = null;
+  let currentNode = head;
+
+  while(currentNode) {
+      const nextNode = currentNode.next;
+      currentNode.next = prevNode;
+
+      prevNode = currentNode;
+      currentNode = nextNode;
+  }
+
+  return prevNode;
+};
+
+// 시간복잡도: O(n)
+// 공간복잡도: O(1)