OJ-Problems-Source/HDOJ/4165_autoAC.cpp
2016-09-04 14:28:52 +08:00

31 lines
568 B
C++

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