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  1. #include <stdio.h>
  2.  
  3. int c;
  4. //a{n} = -6a{n-1} -9a{n-2}, a{1}=1, a{2}=2(再帰あり版)
  5. int rec(int n){
  6. 	c++;
  7. 	if(n == 1){
  8. 		return 1;
  9. 	}
  10. 	else if(n == 2){
  11. 		return 2;
  12. 	}
  13. 	else{
  14. 		return -6*rec(n-1) -9*rec(n-2);
  15. 	}
  16. }
  17.  
  18. int main(void) {
  19.     int n = 4;
  20.     printf("数列a%dの値は%d\n", n, rec(n));
  21.     printf("recの呼び出し回数は%d回\n",c);
  22. 	return 0;
  23. }
  24.  
  25.  
Success #stdin #stdout 0s 5320KB
comments (?)
stdin 
Standard input is empty
stdout 
数列a4の値は108
recの呼び出し回数は5回
https://ideone.com/m6JqTC
language:
C (gcc 8.3)
created:
4 days ago
visibility:
public

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