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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. long long f(int n) {
  5. 	if (n < 2) return 1;
  6.  
  7. 	return n * f(n - 1);
  8. }
  9.  
  10. long long c(int n, int k) {
  11. 	return f(n) / f(k) / f(n - k);
  12. }
  13.  
  14. int main() {
  15. 	int n, k;
  16. 	cin >> n >> k;
  17. 	if (n == 0) {
  18. 		cout << 0;
  19. 	} else if (n == k) {
  20. 		cout << 1;
  21. 	} else {
  22. 		cout << c(n, k);
  23. 	}
  24.  
  25. 	return 0;
  26. }
Success #stdin #stdout 0s 5328KB
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https://ideone.com/9ZTVW8
language:
C++ (gcc 8.3)
created:
6 hours ago
visibility:
public

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