# Sorting Optimization

You are optimizing a sorting algorithm for 100,000 random integers.

## Goal

Maximize `ops_per_sec` — the number of sort operations completed per second.

## Rules

- Edit only `sort.py`
- Your `sort_array(arr)` function must sort the array **in-place** and return it
- The function signature must remain `def sort_array(arr: list) -> list:`
- The result must be correctly sorted (benchmark verifies this)
- Standard library is available

## Hard Rules

- DO NOT attempt to run or execute any scripts — the platform runs them automatically
- DO NOT modify any file other than `sort.py`
