diff --git a/HDU/4825/4825.cpp b/HDU/4825/4825.cpp
new file mode 100644
index 00000000..d3db68f7
--- /dev/null
+++ b/HDU/4825/4825.cpp
@@ -0,0 +1,56 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int t, n, m, a;
+
+struct node {
+    int val;
+    node* next[2];
+
+    ~node() {
+        for (auto& i : next) {
+            delete i;
+        }
+    }
+};
+
+void insert(node* root, int x) {
+    for (int i = 30; i >= 0; i--) {
+        if (root->next[(x >> i) & 1] == nullptr) root->next[(x >> i) & 1] = new node();
+        root = root->next[(x >> i) & 1];
+    }
+    root->val = x;
+}
+
+int query(node* root, int x) {
+    for (int i = 30; i >= 0; i--) {
+        if (root == nullptr) break;
+        if (root->next[!((x >> i) & 1)] != nullptr) {
+            root = root->next[!((x >> i) & 1)];
+        } else {
+            root = root->next[(x >> i) & 1];
+        }
+    }
+    return root->val;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin >> t;
+    for (int i = 1; i <= t; i++) {
+        cout << "Case #" << i << ":" << endl;
+        node* root = new node();
+        cin >> n >> m;
+        for (int i = 0; i < n; i++) {
+            cin >> a;
+            insert(root, a);
+        }
+        for (int i = 0; i < m; i++) {
+            cin >> a;
+            cout << query(root, a) << endl;
+        }
+        delete root;
+    }
+    return 0;
+}