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  1. #include<stdio.h>
  2. #include<math.h>
  3. long long int C(long long int n,long long int r) {
  4.   long long int i,j=1,k=1,res = 1;
  5.   if(r> n/2)
  6.     r = n-r;
  7.  
  8.   for(i = 0;i<r;i++) {
  9. //    printf("J %lld \n",j);
  10.  
  11.  
  12.     res *=  n--;
  13.     res /= i+1;
  14.  
  15.   }
  16.   //printf("%lld %lld\n",j,k);
  17.   return res; 
  18. }
  19.  
  20.  
  21. int main(int argc,char** argv) {
  22.   int T; 
  23.   long long int N, K;
  24.  
  25.   scanf("%d",&T);
  26.   while(T--) {
  27.     scanf("%lld %lld",&N,&K);
  28.    printf("%lld\n", C(N-1,K-1));
  29.   }
  30.   return 0;
  31. }
  32.  
Success #stdin #stdout 0s 4396KB
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https://ideone.com/SmtkMy
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
secret

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