Submission #2532136

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Source Code Expand

#include <stack>
#include <queue>
#include <cstdio>
#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <math.h>
#include <string>
 
using namespace std;

#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,n0,n) for(int i=n0;i<n;i++)
#define Com(i,j,n) for(int i=0;i<n-1;i++)for(int j=i+1;j<n;j++)
#define INF (1<<29)
#define test cout << "test" << endl;

long int MOD = 1000000007;

long int gyaku(long int a){
	int bits[33]={0};
	long int beki[33];
	long int bi=MOD-2;
	beki[0]=a;
	rep(i,32){
		beki[i+1] = (beki[i] * beki[i])%MOD;
	}
	rep(i,32){
		bits[i]=bi%2;
		bi = (bi-bits[i])/2;
	}
	long int ret=1;
	rep(i,32){
		if(bits[i]==1){
			ret = (ret * beki[i])%MOD;
		}
	}
	return ret%MOD;
}

long int bikkuri(long int a){
	return (a==1 || a==0)? 1:((bikkuri(a-1)*a)%MOD);
}

int main (){
	long int NNN,KKK;
	cin >> NNN >> KKK;
	long int n1k=bikkuri(NNN-1+KKK)%MOD;
	long int n1 =bikkuri(NNN-1)%MOD;
	long int ke =bikkuri(KKK)%MOD;
	long int n1ke = (n1*ke)%MOD;
	long int ans = (n1k * gyaku(n1ke))%MOD;

	cout << ans << endl;
	
	return 0;
}

Submission Info

Judge Result