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  1. #include <stdio.h>
  2. //a{n} = -6a{n-1} -9a{n-2}, a{1}=1, a{2}=2(再帰あり版)
  3.  
  4. int c;
  5. int rec(int n){
  6. 	if(n == 1) {
  7. 		c++;
  8. 		return 1;
  9. 	}
  10. 	else if(n == 2) {
  11. 		c++;
  12. 		return 2;
  13. 	}
  14. 	else {
  15. 		c++;
  16. 		return - 6 * rec(n-1) - 9 * rec(n-2);
  17. 	}
  18. 	return c;
  19. }
  20.  
  21. int main(void) {
  22.     int n = 4;
  23.     printf("数列a%dの値は%d\n", n, rec(n));
  24.     printf("この時recが呼び出された回数は%c\n", c);
  25. 	return 0;
  26. }
  27.  
  28.  
Success #stdin #stdout 0s 5320KB
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Standard input is empty
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数列a4の値は108
この時recが呼び出された回数は
https://ideone.com/CgaBv5
language:
C (gcc 8.3)
created:
19 hours ago
visibility:
public

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