feat: 2025-10-27打卡

138.copy-list-with-random-pointer.java

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+/*
+ * @lc app=leetcode id=138 lang=java
+ *
+ * [138] Copy List with Random Pointer
+ */
+
+// @lc code=start
+/*
+// Definition for a Node.
+class Node {
+    int val;
+    Node next;
+    Node random;
+
+    public Node(int val) {
+        this.val = val;
+        this.next = null;
+        this.random = null;
+    }
+}
+*/
+
+class Solution {
+    public Node copyRandomList(Node head) {
+        if(head == null) {
+            return null;
+        }
+        Map<Node, Node> ref = new HashMap<>();
+        Node cur = head;
+        while(cur != null) {
+            Node cp = new Node(cur.val);
+            ref.put(cur, cp);
+            cur = cur.next;
+        }
+        cur = head;
+        while(cur != null) {
+            Node nd = ref.get(cur);
+            nd.next = ref.get(cur.next);
+            nd.random = ref.get(cur.random);
+            cur = cur.next;
+        }
+        return ref.get(head);
+    }
+}
+// @lc code=end
+