【数论】nefu119 组合素数

算组合数中的素因子p的个数，基本同这题

http://www.cnblogs.com/autsky-jadek/p/6592194.html

#include
using namespace std;
typedef long long ll;
int calc(int n,int p){
	int res=0;
	ll t=p;
	while(t<=(ll)n){
		res+=(n/(int)t);
		t*=(ll)p;
	}
	return res;
}
int T,n,m;
int main(){
//	freopen("b.in","r",stdin);
	scanf("%d",&T);
	for(;T;--T){
		scanf("%d%d",&n,&m);
		printf("%d\n",calc(2*n,m)-2*calc(n,m));
	}
	return 0;
}

转载于:https://www.cnblogs.com/autsky-jadek/p/6592239.html