37 lines
593 B
C++
37 lines
593 B
C++
// 129
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#include <bits/stdc++.h>
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using namespace std;
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vector<int> ans;
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int stk[25], tot, n, cnt;
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void dfs(int now)
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{
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if (cnt >= 20)
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return;
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if (now > n)
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{
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cnt++;
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for (auto x : ans)
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cout << x;
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for (int i = tot - 1; i >= 0; i--)
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cout << stk[i];
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puts("");
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return;
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}
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if (tot)
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{
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ans.push_back(stk[--tot]);
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dfs(now);
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stk[tot++] = ans.back();
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ans.pop_back();
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}
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stk[tot++] = now;
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dfs(now + 1);
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tot--;
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}
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int main()
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{
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cin >> n;
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dfs(1);
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return 0;
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} |