solution: reverse-linked-list using iteration

Author: Jeongwon Na

reverse-linked-list/njngwn.java

@@ -0,0 +1,27 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+// Time Complexity: O(n)
+// Sprace Compexity: O(1)
+class Solution {
+    public ListNode reverseList(ListNode head) {
+        ListNode prevNode = null;
+        ListNode currNode = head;
+
+        while (currNode != null) {
+            ListNode nextNode =  currNode.next;
+            currNode.next = prevNode;
+            prevNode = currNode;
+            currNode = nextNode;
+        }
+
+        return prevNode;
+    }
+}