P1044 [NOIP2003 普及组] 栈

#include<bits/stdc++.h>
using namespace std;
#define x first
#define y second
typedef pair<int,int> PII;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef vector<string> VS;
typedef vector<int> VI;
typedef vector<vector<int>> VVI;
vector<int> vx;
inline int mp(int x) {return upper_bound(vx.begin(),vx.end(),x)-vx.begin();}
inline int log_2(int x) {return 31-__builtin_clz(x);}
inline int popcount(int x) {return __builtin_popcount(x);}
inline int lowbit(int x) {return x&-x;}
const int N = 1001;
ll C[N][N];
void init_C()
{
	for(int i=0;i<N;++i) C[i][0] = 1;
	for(int i=1;i<N;++i)
	 for(int j=1;j<=i;++j)
	 {
	 	C[i][j] = C[i-1][j] + C[i-1][j-1];
	 }
}
void solve()
{
	init_C();
	int n;
	cin>>n;
	cout<<C[2*n][n]/(n+1)<<'\n';
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int T = 1;
	//cin>>T;
	while(T--)
	{
		solve();
	}
}