poj1942

简单题

View Code
   
     
#include < iostream >
#include
< cstdio >
#include
< cstdlib >
#include
< cstring >
using namespace std;

long long n, m;

long long com( long long n, long long r)
{
if (n - r < r)
r
= n - r;
long long i, j, s = 1 ;
for (i = 0 , j = 1 ; i < r; i ++ )
{
s
*= (n - i);
for (; j <= r && s % j == 0 ; ++ j) s /= j;
}
return s;
}

int main()
{
// freopen("t.txt", "r", stdin);
while (scanf( " %lld%lld " , & n, & m), n | m)
printf(
" %lld\n " , com(n + m, n));
return 0 ;
}

你可能感兴趣的:(poj)