Submission #232150

#	Time	Username	Problem	Language	Result	Execution time	Memory
232150		Dremix10	Rack (eJOI19_rack)	C++17	100 / 100	5 ms	384 KiB

rack

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;


ll expo(ll x, ll n, ll m){
    if(n==0)return 1;
    ll u=expo(x,n/2,m);
    u=(u*u)%m;
    if(n%2)u=(u*x)%m;
    return u;
}


int main (){
long long n,k;
cin>>n>>k;
n--;
long long start;

if(n>59)
    start=1;
else{
    ll temp=1e18;
    ll res=expo(2,n,temp);
    if(k<=res)
        start=1;
    else{
        start=2;
        k-=res;
    }
}
//cout<<start<<endl;

int mod=1e9+7;

while(k>(ll)1){

    if(k%2){
        k/=2;
        k++;
    }
    else{
        k/=2;
        start+=expo(2,n,mod);
        start%=mod;
    }
    n--;

}

cout<<start<<endl;

}

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