Submission #19395

#	Time	Username	Problem	Language	Result	Execution time	Memory
19395		camille	Σ (kriii4_P2)	C++98	100 / 100	29 ms	1716 KiB

P2

#include <iostream>
using namespace std;
typedef long long  lld;
lld a,x,mod=1e9+7,t,ret;

lld foo(lld idx){
    if(idx==1) return a;
    lld k = foo(idx/2)%mod;
    if(idx%2) return (((k*k)%mod)*a)%mod;
    return (k*k)%mod;
}

int main(){
    cin>>t;
    while(t--){
        cin>>a>>x;
        a%=mod;
        ret+=(x*foo(mod-2))%mod;
        ret%=mod;
    }
    cout<<ret<<endl;
}

• Subtask 1: 100 / 100