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  1. #include <stdio.h>
  2. typedef unsigned long long huge;
  3. huge min(huge a,  huge b) {
  4.     return (a<b) ?  a : b;
  5. } 
  6. huge calc(huge n, huge k){
  7.     huge Up=k, Dn=0; 
  8.     while(Up-Dn>1){ 
  9.         huge Md=(Up+Dn)/2;
  10.         huge cnt=0,  aux=1;
  11.         for(huge i=1; i<=min(n,Md); ++i){
  12.                 aux*=Md-i+1;
  13.                 aux/=i;
  14.                 cnt+=aux;
  15.                 if(cnt>=k)
  16.                      break;
  17.         }
  18.         if(cnt<k)
  19.             Dn=Md;
  20.          else 
  21.             Up=Md;
  22.          } 
  23.     return Dn+1; 
  24.     }
  25.  int main(){
  26.     huge n,k, ans[1000];
  27.     int tot=0;
  28.     scanf("%llu %llu",&n,&k); 
  29.     while(n>0 && k>0){
  30.          n=min(60LLU,n);
  31.          ans[tot++]=calc(n,k);
  32.          scanf("%llu %llu",&n,&k);
  33.      }
  34.      for(int i=0; i<tot; ++i)
  35.          printf("%llu\n",ans[i]);
  36.      return 0; 
  37. }
Success #stdin #stdout 0s 15240KB
comments (?)
stdin 
2 5
0 0
stdout 
3
https://ideone.com/KwNNiu
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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