diff --git a/17.cpp b/17.cpp
new file mode 100644
index 0000000..e4ac41e
--- /dev/null
+++ b/17.cpp
@@ -0,0 +1,69 @@
+// 113
+#include <bits/stdc++.h>
+using namespace std;
+// --- down for luogu ---
+// bool compare(int a, int b)
+// {
+//     cout << "? " << a << ' ' << b << endl;
+//     bool t;
+//     cin >> t;
+//     return t;
+// }
+// --- up for luogu ---
+class Solution
+{
+public:
+    vector<int> tmp, a;
+    int tot = 0;
+    void ms(int l, int r)
+    {
+        if (l == r)
+            return;
+        int mid = l + r >> 1;
+        ms(l, mid);
+        ms(mid + 1, r);
+        int i = l, j = mid + 1, tot = l;
+        while (i <= mid && j <= r)
+            if (compare(a[i], a[j]))
+                tmp[tot++] = a[i++];
+            else
+                tmp[tot++] = a[j++];
+        while (i <= mid)
+            tmp[tot++] = a[i++];
+        while (j <= r)
+            tmp[tot++] = a[j++];
+        for (int k = l; k <= r; ++k)
+            a[k] = tmp[k];
+    }
+    vector<int> specialSort(int N)
+    {
+        a.resize(1005);
+        tmp.resize(1005);
+        for (int i = 1; i <= N; ++i)
+        {
+            a[i] = i;
+        }
+        ms(1, N);
+        vector<int> res(N);
+        for (int i = 0; i < N; ++i)
+        {
+            res[i] = a[i + 1];
+        }
+        return res;
+    }
+};
+// --- down for luogu ---
+// int main()
+// {
+//     int n;
+//     scanf("%d", &n);
+//     Solution k;
+//     vector<int> ans = k.specialSort(n);
+//     printf("! ");
+//     for (int i = 0; i < n; ++i)
+//     {
+//         printf("%d ", ans[i]);
+//     }
+//     return 0;
+// }
+// --- up for luogu ---
\ No newline at end of file