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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.  int c=0;
  4. int rec(int n){
  5. 	if(n==1){
  6. 		 c++;
  7. 		 return 1;
  8.  
  9. 	}
  10. 	else if(n==2){
  11. 		 c++;
  12. 		 return 2;
  13.  
  14. 	}
  15. 	else{
  16. 		 c++;
  17. 		 return -6*rec(n-1)-9*rec(n-2);
  18.  
  19. 	}
  20.  
  21. }
  22.  
  23. int main(void) {
  24.     int n = 4;
  25.     printf("数列a%dの値は%d\n", n, rec(n));
  26.     printf("このときのrecの呼び出し回数は%d",c);
  27. 	return 0;
  28. }
  29.  
  30.  
Success #stdin #stdout 0s 5316KB
comments (?)
stdin 
Standard input is empty
stdout 
数列a4の値は108
このときのrecの呼び出し回数は5
https://ideone.com/tklW7j
language:
C (gcc 8.3)
created:
4 days ago
visibility:
public

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