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  1. #include <iostream>
  2. using namespace std;
  3.  
  4.  
  5. int main()
  6. {
  7.     int t;
  8.     cin>>t;
  9.     int k,n;
  10.     long double pom2;
  11.     while(--t+1)
  12.     {
  13.         cin>>n>>k;
  14.         if(k==n)
  15.         {
  16.             cout<<1<<endl;
  17.         }
  18.         else
  19.         {
  20.         if(k>(n-k)){
  21.             pom2=1;
  22.             for(int i=n;i>k;--i)
  23.             {
  24.                 pom2*=i*1.0/(i-k);
  25.             }
  26.         }
  27.         else
  28.         {
  29.             pom2=n-k+1;
  30.             for(int i=1;i<k;++i)
  31.                 pom2*=(n-k+i+1)*1.0/(k-i+1);
  32.         }
  33.         cout.flags(ios::fixed);
  34.         cout<<pom2<<endl;
  35.         }
  36.     }
  37.     return 0;
  38.  
  39. }
  40.  
Success #stdin #stdout 0s 15240KB
comments (?)
stdin
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1
1000 3
stdout
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166167000.000000
https://ideone.com/erLGkr
language:
C++ (gcc 8.3)
created:
7 years ago
visibility:
public

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