31 lines
568 B
C++
31 lines
568 B
C++
#include<cstdio>
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#include<cmath>
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#include<stack>
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#include<cstring>
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#include<string>
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#include<iostream>
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#include<algorithm>
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using namespace std;
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#define clr(x) memset(x,0,sizeof(x))
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long long dp[31][31];
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bool inti(){
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clr(dp);
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for(int i=0;i<=30;i++){
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dp[i][0]=1;
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}
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for(int i=1;i<=30;i++){
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for(int j=1;j<=i;j++){
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dp[i][j]=dp[i-1][j]+dp[i][j-1];
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}
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}
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return true;
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}
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int main(){
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inti();
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int i,j,k,m,n;
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while(cin>>n&&n){
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cout<<dp[n][n]<<endl;
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}
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return 0;
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}
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