Submission #763761

#	Time	Username	Problem	Language	Result	Execution time	Memory
763761		NemanjaSo2005	Rack (eJOI19_rack)	C++17	100 / 100	11 ms	2328 KiB

rack

#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll N,K,MOD=1e9+7;
string ubin(ll x){
   string ret;
   while(x){
      ret.push_back(x%2);
      x/=2;
   }
   return ret;
}
ll udec(string a){
   ll st=1,ret=0;
   for(int i=a.size()-1;i>=0;i--){
      ret=(ret+a[i]*st)%MOD;
      st=(st*2)%MOD;
   }
   return ret;
}
int main(){
   cin>>N>>K;
   string a=ubin(K-1);
   while(a.size()<N)
      a.push_back(0);
   cout<<udec(a)+1<<endl;
   return 0;
}

Compilation message (stderr)

rack.cpp: In function 'int main()':
rack.cpp:24:18: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   24 |    while(a.size()<N)
      |          ~~~~~~~~^~

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