Lucas定理

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
#include<ctime>
#include<queue>
#include<vector>
using namespace std;
const int N=100005;
int n,m,p;
long long A[N+5],B[N+5];
int C(int n,int m,int p){
    if(m>n){
		return 0;
	}
    return A[n]*B[n-m]%p*B[m]%p;
}
int Lucas(int n, int m, int p){
    if(!m){
		return 1;
	}
    return C(n%p, m%p, p)*Lucas(n/p, m/p, p)%p;
}
int main(){
    int t;
    scanf("%d", &t);
    while(t--){
		scanf("%d%d%d",&n,&m,&p);
		A[0]=B[0]=A[1]=B[1]=1;
		n+=m;
		for(int i=2;i<=p;i++){
			B[i]=-(p/i)*B[p%i]%p;
		}
		for(int i=2;i<=p;i++){
			A[i]=A[i-1]*i%p,
			B[i]=B[i-1]*B[i]%p;
		}
		printf("%d\n",(Lucas(n,m,p)+p)%p);
	}
    return 0;
}
posted @ 2019-10-20 11:15  prestige  阅读(93)  评论(0编辑  收藏  举报