reverse-linked-list solution

Author: jdy8739

reverse-linked-list/jdy8739.js

@@ -0,0 +1,43 @@
+
+/**
+ * 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) {
+    if (head === null) {
+      return null;
+    }
+  
+    if (head.next === null) {
+      return head;
+    }
+  
+    const stack = [];
+  
+    let nextNode = head;
+    
+    while (nextNode) {
+      stack.push(nextNode);
+  
+      nextNode = nextNode.next;
+    }
+  
+    for (let i=stack.length - 1; i>=0; i--) {
+      if (i === 0) {
+          stack[i].next = null;
+      } else {
+          stack[i].next = stack[i - 1];
+      }
+    }
+  
+  return stack[stack.length - 1];
+};
+
+// 시간복잡도 O(2n)