Submission #19338

#	Time	Username	Problem	Language	Result	Execution time	Memory
19338		gs13068	Σ (kriii4_P2)	C++98	100 / 100	6 ms	1084 KiB

P2

#include <cstdio>

const int p = 1000000007;

int f(int x, int y)
{
	return y & 1 ? (long long)f(x, y ^ 1)*x%p : y ? f((long long)x*x%p, y >> 1) : 1;
}

int main()
{
	int n, a, b, r = 0;
	scanf("%d", &n);
	while (n--)
	{
		scanf("%d%d", &a, &b);
		r = (r + (long long)f(a, p - 2)*b) % p;
	}
	printf("%d", r);
}

• Subtask 1: 100 / 100