Submission #260076

#	Time	Username	Problem	Language	Result	Execution time	Memory
260076		mosiashvililuka	Rack (eJOI19_rack)	C++14	100 / 100	36 ms	30840 KiB

rack

#include<bits/stdc++.h>
using namespace std;
long long a,b,c,d,e,i,j,ii,jj,zx,xc,k,mod=1000000007LL,ka;
long long xar(long long q, long long w){
    if(w==0) return 1LL;
    long long qw=xar(q,w/2);
    if(w%2==0) return (qw*qw); else return ((qw*qw)*q);
}
long long rec(long long q, long long w){
    if(q==1){
        return w;
    }
    if(q-1>=ka||xar(2,q-1)>=w){
        return (rec(q-1,w)*2-1+mod)%mod;
    }else{
        return (rec(q-1,w-xar(2,q-1))*2)%mod;
    }
}
int main(){
    ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    cin>>a>>k;
    for(ka=1; ; ka++){
        if(xar(2,ka)>=k) break;
    }
    cout<<rec(a,k);
    return 0;
}

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