17 lines
364 B
C++
17 lines
364 B
C++
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#include<bits/stdc++.h>
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using namespace std;
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typedef long long ll;
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const int N = 40;
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ll c[N][N];
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int main(){
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for(int i = 0; i < N; i++){
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for(int j = 1; j <= i; j++)
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if(!j)c[i][j] = 1;
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else
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c[i][j] = c[i-1][j] + c[i-1][j-1];
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}
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int n;
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cin >> n;
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cout << c[n*2][n]/(n+1) << endl;
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return 0;
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}
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