20240525 Finished

LeetCodeSharp/Problems/Solution138.cs

@@ -0,0 +1,87 @@
+// [138] Copy List with Random Pointer
+
+using System.Collections.Generic;
+
+namespace LeetCodeSharp.Problems138
+{
+    // Submission codes start here
+
+    /*
+// Definition for a Node.
+public class Node {
+    public int val;
+    public Node next;
+    public Node random;
+
+    public Node(int _val) {
+        val = _val;
+        next = null;
+        random = null;
+    }
+}
+*/
+    public class Node
+    {
+        public int val;
+        public Node next;
+        public Node random;
+
+        public Node(int _val)
+        {
+            val = _val;
+            next = null;
+            random = null;
+        }
+    }
+
+    public class Solution
+    {
+        private readonly List<Node> _nodes = new List<Node>();
+
+        public Node CopyRandomList(Node head)
+        {
+            _nodes.Clear();
+
+            Node newHead = null;
+            Node newNow = null;
+            Node now = head;
+
+            while (now != null)
+            {
+                Node newNode = new Node(now.val);
+                now.val = _nodes.Count;
+                newNode.random = now.random;
+                _nodes.Add(newNode);
+
+                if (newHead == null)
+                {
+                    newHead = newNode;
+                    newNow = newNode;
+                }
+                else
+                {
+                    newNow.next = newNode;
+                    newNow = newNode;
+                }
+
+                now = now.next;
+            }
+
+            newNow = newHead;
+
+            while (newNow != null)
+            {
+                if (newNow.random != null)
+                {
+                    newNow.random = _nodes[newNow.random.val];
+                }
+
+                newNow = newNow.next;
+            }
+
+            return newHead;
+        }
+    }
+
+    // Submission codes end here
+}