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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. int main() {
  5. 	int t;
  6. 	cin >> t;
  7. 	while(t--){
  8. 		int n;
  9. 		cin >> n;
  10. 		int ara[n];
  11. 		for(int i=0; i<n; i++)ara[i] = i+1;
  12. 		if(n%2 == 0){
  13. 			for(int i=0; i<n; i+=2){
  14. 				int temp = ara[i+1];
  15. 				ara[i+1] = ara[i];
  16. 				ara[i] = temp;
  17. 			}
  18. 		}
  19. 		else{
  20. 			for(int i=1; i<n-1; i+=2){
  21. 				int temp = ara[i+1];
  22. 				ara[i+1] = ara[i];
  23. 				ara[i] = temp;
  24. 			}
  25. 		}
  26.  
  27. 		for(int i=0; i<n; i++)cout << ara[i] << " ";
  28. 		cout << endl;
  29. 	}
  30. 	return 0;
  31. }
Success #stdin #stdout 0.01s 5280KB
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stdin
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5
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stdout
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1 
1 3 2 
1 3 2 5 4 
2 1 4 3 
2 1 4 3 6 5
https://ideone.com/X9nYH3
language:
C++ (gcc 8.3)
created:
16 hours ago
visibility:
public

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