Submission #19353

#	Time	Username	Problem	Language	Result	Execution time	Memory
19353		algoshipda	Σ (kriii4_P2)	C++14	100 / 100	19 ms	1720 KiB

P2

#include <bits/stdc++.h>
using namespace std;
typedef long long lld;
const int MOD = 1e9 + 7;

int gcd(int a, int b)
{
	return b ? gcd(b, a % b) : a;
}
int fpow(int n, int k)
{
	if(k == 0) return 1;
	if(k % 2){
		return 1ll * n * fpow(n, k - 1) % MOD;
	}
	int h = fpow(n, k / 2);
	return 1ll * h * h % MOD;
}

int main()
{
	int t;
	cin >> t;
	int s = 0;
	while(t--){
		int n, k;
		cin >> k >> n;
		int g = gcd(k, n);
		k /= g;
		n /= g;
		s += 1ll * n * fpow(k, MOD - 2) % MOD;
		s %= MOD;
	}
	cout << s << '\n';
}

• Subtask 1: 100 / 100