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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;
  4. int rec(int n) {
  5. 	c++;
  6.     if (n == 1) {
  7.         return 1;
  8.  
  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. int main(void) {
  18.     int n = 5;
  19.     printf("数列a%dの値は%d\n", n, rec(n));
  20.      printf("rec呼び出し回数は%d",c);
  21.     return 0;
  22. }
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin 
Standard input is empty
stdout 
数列a5の値は-459
rec呼び出し回数は9
https://ideone.com/fx2si6
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

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