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  1. #include <stdio.h>
  2. int c = 0;
  3. //a[n] = -6a[n-1] - 9a[n-2], a[1]=1, a[2]=2 (得得あり版)
  4. int rec(int n){
  5. c++;
  6. if(n == 1){
  7. return 1;
  8. }
  9. else if(n == 2){
  10. return 2;
  11. }
  12. else{
  13. return -6*rec(n-1) - 9*rec(n-2);
  14. }
  15. }
  16. int main(void){
  17. int n = 4;
  18. printf("数列a%dの値は%d\n", n, rec(n));
  19. printf("このときrecの呼び出し回数は%d\n", c);
  20. return 0;
  21. }
Success #stdin #stdout 0s 5320KB
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Standard input is empty
stdout
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数列a4の値は108
このときrecの呼び出し回数は5
https://ideone.com/n0MkyR
language:
C (gcc 8.3)
created:
18 hours ago
visibility:
public

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