Codeforces 1512A. Spy Detected! Solution

  Solution in C++: 

///******Bismillahir-Rahmanir-Rahim******///

///AH Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh 

1. #include <iostream>
2. using namespace std;
3. int fda(int ar[],int n)
4. {
5.  
6. if (n == 1)
7. return -1;
8. if (n == 2)
9. return 0;
10. if (ar[0] == ar[1] && ar[0] != ar[2])
11. return 2;
12. if (ar[0] == ar[2] && ar[0] != ar[1])
13. return 1;
14. if (ar[1] == ar[2] && ar[0] != ar[1])
15. return 0;
16. for (int i = 3; i < n; i++)
17. if (ar[i] != ar[i - 1])
18. return i;
19.  
20. return -1;
21. }
22. int main()
23. {
24. int j,tst,n;
25. cin>>tst;
26. while(tst--)
27. {
28. cin>>n;
29. int ar[n+9];
30. for(int j=0; j<n; j++)
31. {
32. cin>>ar[j];
33. }
34. cout << fda(ar,n)+1<<endl;
35.  
36. }
37. return 0;
38. }