From eb7a278b1b6daa092d5641543982d1a02d43f188 Mon Sep 17 00:00:00 2001
From: hanyixuanten <105723997+hanyixuanten@users.noreply.github.com>
Date: Mon, 24 Aug 2026 20:06:11 +0800
Subject: [PATCH] new file:   0x10/3.cpp

---
 0x10/3.cpp | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 0x10/3.cpp

diff --git a/0x10/3.cpp b/0x10/3.cpp
new file mode 100644
index 0000000..d798b18
--- /dev/null
+++ b/0x10/3.cpp
@@ -0,0 +1,37 @@
+// 129
+#include <bits/stdc++.h>
+using namespace std;
+vector<int> ans;
+int stk[25], tot, n, cnt;
+void dfs(int now)
+{
+    if (cnt >= 20)
+        return;
+    if (now > n)
+    {
+        cnt++;
+        for (auto x : ans)
+            cout << x;
+        for (int i = tot - 1; i >= 0; i--)
+            cout << stk[i];
+        puts("");
+        return;
+    }
+    if (tot)
+    {
+        ans.push_back(stk[--tot]);
+        dfs(now);
+        stk[tot++] = ans.back();
+        ans.pop_back();
+    }
+    stk[tot++] = now;
+    dfs(now + 1);
+    tot--;
+}
+
+int main()
+{
+    cin >> n;
+    dfs(1);
+    return 0;
+}
\ No newline at end of file