Submission #19057

#	Time	Username	Problem	Language	Result	Execution time	Memory
19057		kriii	Σ (kriii4_P2)	C++14	100 / 100	0 ms	1084 KiB

P2

#include <stdio.h>

const long long mod = 1000000007;

long long fpow(long long a, long long p)
{
	a = (a % mod + mod) % mod;
	p = (p % (mod - 1) + mod - 1) % (mod - 1);
	long long r = 1;
	while (p){
		if (p & 1) r = r * a % mod;
		a = a * a % mod;
		p >>= 1;
	}
	return r;
}

int main()
{
	long long ans = 0;
	int M; scanf ("%d",&M); while (M--){
		long long N,S; scanf ("%lld %lld",&N,&S); ans = (ans + fpow(N,-1) * S) % mod;
	}
	printf ("%lld\n",ans);

	return 0;
}

• Subtask 1: 100 / 100