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  1. #include <iostream>
  2. #include<bits/stdc++.h>
  3. using namespace std;
  4. int b[100001]={0},count1=0;
  5. bool arr[100001]{1,1,0,0};
  6. int func(int i,int *a)
  7. {   if(b[i]!=0)
  8.      return 1;
  9. 	if(a[i]==0)
  10. 	{b[i]=1;
  11. 	return 1;
  12. 	}
  13. 	if(b[a[i]]==0)
  14. 	b[i]=1+func(a[i],a);
  15. 	else
  16. 	b[i]=1+b[a[i]];
  17. 	if(b[i]+i-1==2 || ((b[i]+i-1)%2!=0 && arr[(b[i]+i-1)]==0))
  18. 	count1++;
  19. 	return b[i];
  20.  
  21. }
  22. int main() {
  23. 	// your code goes here
  24. 	int t,i,j;
  25. 	cin>>t;
  26. 	arr[1]=1;
  27. 		for(i=3;i*i<316;i=i+2)
  28. 	    { 
  29. 	    if(arr[i]!=1)
  30. 	       {
  31. 	        for(j=i*i;j<=10000;j=j+2*i)
  32. 	        {
  33. 	            arr[j]=1;
  34. 	        }
  35. 	       }
  36. 	    }
  37. 	while(t--)
  38. 	{
  39. 	int a[100002],i,n;
  40. 	count1=0;
  41. 	cin>>n;
  42. 	for(i=1;i<=n;i++)
  43. 	{
  44. 		cin>>a[i];
  45. 		b[i]=0;
  46. 	}
  47. 	for(i=1;i<=n;i++)
  48. 	  {func(i,a);
  49. 	  }	
  50. 	  cout<<count1<<"\n";
  51. 	}
  52.  
  53. 	return 0;
  54. }
Success #stdin #stdout 0s 15992KB
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https://ideone.com/c3YPjN
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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