Submission #32308

#	Time	Username	Problem	Language	Result	Execution time	Memory
32308		TAMREF	Σ (kriii4_P2)	C++11	100 / 100	3 ms	2176 KiB

P2

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1e9+7;
ll npow(ll a, ll n){
    ll res = 1, pval = a%mod;
    for(;n;n>>=1,pval=pval*pval%mod){
        if(n&1) res = res*pval%mod;
    }
    return res;
}
int main(){
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int m;
    ll x=0,a,b;
    for(cin>>m;m--;){
        cin>>a>>b;
        x = (x + (b*npow(a,mod-2)%mod))%mod;
    }
    cout<<x<<'\n';
}

• Subtask 1: 100 / 100