TIOJ 1308 幾組解咧(其一)

#include <cstdio>
#include <cstdlib>
#include <vector>
#include <string.h>
using namespace std;
long long c(int x, int y){
    long long ans = 1;
    for (long long i = 1; i <= y; ++i){
        ans *= (long long)x - i + 1;
        ans /= i;
    }
    return ans;
}

int main(){
    int n, m;
    while(true){
        scanf("%d %d", &n, &m);
        if(n == 0)
            break;
        
        printf("%lld\n", c(n + m - 1, m));
    }
}