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  1. #include <stdio.h>
  2.  
  3. int c=0;
  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 = 5;
  20.     printf("数列a%dの値は%d\n", n, rec(n));
  21.     printf("このときrecの呼び出し回数は%d",c);
  22.     return 0;
  23. }
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin 
Standard input is empty
stdout 
数列a5の値は-459
このときrecの呼び出し回数は9
https://ideone.com/7jY6Ry
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

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