First one (2027 ms): 253857814
The second one (249 ms): 253859120

In my observation, both of them have a time complexity of O(n²logn²)

• First one: I created a vector of pairs that have a size of nearly n² and inserted all of them in a map which will take O(n²logn²) time complexity.
• Second one: I created a vector of pairs with a similar size of nearly n². And I then sorted it which will take O(n²logn²) time complexity.

Then why the second approach is taking so much less time?