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  1. #include <stdio.h>
  2. //まず
  3. int factorial(int n) {
  4.     int result = 1;
  5.     for(int i = 1; i <= n; i++) {
  6.         result *= i;
  7.     }
  8.     return result;
  9. }
  10.  
  11. //次に
  12. int comb(int m, int k) {
  13.     return factorial(m) / (factorial(k) * factorial(m - k));
  14. }
  15. int main(void) {
  16.     int m, k;
  17.     scanf("%d", &m);
  18.     scanf("%d", &k);
  19.  
  20.     if(m < k) {
  21.         printf("エラー\n");
  22.     } else if(m > 12) {
  23.         printf("エラー\n");
  24.     } else {
  25.         int combination = comb(m, k);
  26.         printf("%d個の中から%d個を取り出す組合せ数は、%d通りです。\n", m, k, combination);
  27.     }
  28.  
  29.     return 0;
  30. }
  31.  
Success #stdin #stdout 0s 5280KB
comments (?)
stdin
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10 3
stdout
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10個の中から3個を取り出す組合せ数は、120通りです。
https://ideone.com/NtmIEO
language:
C (gcc 8.3)
created:
134 days ago
visibility:
public

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