Custom sort in java and it's time complexity

Question

int [][] countArr = new int[123][2];
Arrays.sort(countarr, (a,b) -> Integer.compare(b[0], a[0]));

what will be the time complexity for this custom sort in java?

Answer 1

Your example is not a custom sort. Your example might be "a custom comparison" + "the standard sort". You can multiply the complexities of the comparison and the sort. Java standard sort complexity is explained below:

Arrays.sort uses dual-pivot Quicksort on primitives. It offers O(n log(n)) performance and is typically faster than traditional (one-pivot) Quicksort implementations

Collections.sort, it uses modified mergesort and offers guaranteed O(n log(n)) performance.

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