Submission #592477

#	Time	Username	Problem	Language	Result	Execution time	Memory
592477		Iwanttobreakfree	Rack (eJOI19_rack)	C++98	100 / 100	1 ms	368 KiB

rack

#include <iostream>
#include <vector>
using namespace std;
#define int long long
const int mod=1e9+7;
int bin_exp(int n,int k){
    if(!k)return 1;
    int x=bin_exp(n,k/2);
    x=(x*x)%mod;
    if(k&1)return (x*n)%mod;
    return x;
}
signed main(){
    int n,x,cnt=1,ans=0;
    cin>>n>>x;
    x--;
    while(x){
        if(x&1)ans=(ans+bin_exp(2,n-cnt))%mod;
        x/=2;
        cnt++;
    }
    cout<<ans+1<<'\n';
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 60 / 60