⚡️ Speed up function sorter by 17%

[codeflash-ai]

📄 17% (0.17x) speedup for sorter in src/async_examples/concurrency.py

⏱️ Runtime : 691 milliseconds → 590 milliseconds (best of 27 runs)

📝 Explanation and details

The optimized code implements two key improvements to the bubble sort algorithm:

1. Early termination with swap detection: Added a swapped flag that tracks whether any swaps occurred during a pass. If no swaps happen, the array is already sorted and the algorithm exits early via break. This is particularly effective for already-sorted or nearly-sorted inputs.

2. Reduced comparison range: Changed the inner loop from range(len(arr) - 1) to range(len(arr) - 1 - i). After each outer loop iteration, the largest i elements are guaranteed to be in their final positions at the end of the array, so we don't need to check them again.

Performance impact: The line profiler shows the inner loop iterations dropped from 2.3M to 1.1M (52% reduction), and overall runtime improved by 17%. The optimizations are most effective for:

• Already sorted lists (early exit after first pass)
• Partially sorted lists (fewer passes needed)
• Large arrays where avoiding redundant comparisons at the end provides significant savings

These changes maintain identical sorting behavior and async functionality while dramatically reducing unnecessary work, especially evident in test cases with ordered or semi-ordered data.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 84 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

import asyncio  # used to run async functions
import random  # used for generating large random lists
import sys  # used for edge case with maxsize

import pytest  # used for our unit tests
from src.async_examples.concurrency import sorter

# ---------------------------
# Basic Test Cases
# ---------------------------

@pytest.mark.asyncio
async def test_sorter_empty_list():
    # Test sorting an empty list
    arr = []
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_single_element():
    # Test sorting a single-element list
    arr = [42]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_sorted_list():
    # Test sorting an already sorted list
    arr = [1, 2, 3, 4, 5]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_reverse_sorted_list():
    # Test sorting a reverse sorted list
    arr = [5, 4, 3, 2, 1]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_unsorted_list():
    # Test sorting a typical unsorted list
    arr = [3, 1, 4, 2, 5]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_duplicates():
    # Test sorting a list with duplicate values
    arr = [4, 2, 2, 3, 1, 4]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_negative_numbers():
    # Test sorting a list with negative numbers
    arr = [-3, -1, -2, 0, 2, 1]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_mixed_types():
    # Test sorting a list with both positive and negative numbers
    arr = [0, -1, 1, -2, 2]
    result = await sorter(arr.copy())

# ---------------------------
# Edge Test Cases
# ---------------------------

@pytest.mark.asyncio
async def test_sorter_all_equal():
    # Test sorting a list where all elements are equal
    arr = [7, 7, 7, 7, 7]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_large_numbers():
    # Test sorting a list with very large and very small integers
    arr = [sys.maxsize, -sys.maxsize, 0, 999999999, -999999999]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_concurrent_calls():
    # Test concurrent execution of the sorter function with different inputs
    arr1 = [3, 2, 1]
    arr2 = [9, 8, 7, 6]
    arr3 = [5, 10, 0, -1]
    results = await asyncio.gather(
        sorter(arr1.copy()),
        sorter(arr2.copy()),
        sorter(arr3.copy())
    )

@pytest.mark.asyncio
async def test_sorter_cancellation():
    # Test cancellation of the sorter coroutine
    arr = [5, 3, 1, 2, 4]
    task = asyncio.create_task(sorter(arr.copy()))
    await asyncio.sleep(0.000005)  # Let the task start
    task.cancel()
    try:
        await task
    except asyncio.CancelledError:
        pass  # Expected behavior

@pytest.mark.asyncio
async def test_sorter_exception_handling():
    # Test that sorter raises an exception if input is not a list
    with pytest.raises(TypeError):
        await sorter("not a list")  # Should fail as string is iterable but not list

# ---------------------------
# Large Scale Test Cases
# ---------------------------

@pytest.mark.asyncio
async def test_sorter_large_list():
    # Test sorting a large list of random numbers (under 1000 elements)
    arr = random.sample(range(-10000, -9000), 999)
    expected = sorted(arr)
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_many_concurrent_large_lists():
    # Test concurrent sorting of many large lists
    lists = [random.sample(range(-10000, -9000), 100) for _ in range(10)]
    expected = [sorted(lst) for lst in lists]
    results = await asyncio.gather(*(sorter(lst.copy()) for lst in lists))

@pytest.mark.asyncio
async def test_sorter_performance_under_load():
    # Test performance under concurrent load (timing, but no assert on time)
    lists = [random.sample(range(1000), 50) for _ in range(20)]
    # Await all sorts concurrently
    results = await asyncio.gather(*(sorter(lst.copy()) for lst in lists))
    for lst, result in zip(lists, results):
        pass

# ---------------------------
# Async/Await Behavior Tests
# ---------------------------

@pytest.mark.asyncio
async def test_sorter_returns_coroutine():
    # Test that sorter returns a coroutine and must be awaited
    arr = [2, 1]
    codeflash_output = sorter(arr.copy()); coro = codeflash_output
    result = await coro

@pytest.mark.asyncio
async def test_sorter_does_not_block_event_loop():
    # Test that sorter yields control to event loop (simulate by running with another task)
    arr = [3, 2, 1]
    side_effect = []
    async def side_task():
        await asyncio.sleep(0.000005)
        side_effect.append("ran")
    await asyncio.gather(sorter(arr.copy()), side_task())
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
import asyncio  # used to run async functions

import pytest  # used for our unit tests
from src.async_examples.concurrency import sorter

# -------------------------
# Basic Test Cases
# -------------------------

@pytest.mark.asyncio
async def test_sorter_empty_list():
    # Test sorting an empty list
    arr = []
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_single_element():
    # Test sorting a single-element list
    arr = [42]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_sorted_list():
    # Test sorting an already sorted list
    arr = [1, 2, 3, 4, 5]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_reverse_sorted_list():
    # Test sorting a reverse-sorted list
    arr = [5, 4, 3, 2, 1]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_unsorted_list():
    # Test sorting a typical unsorted list
    arr = [3, 1, 4, 5, 2]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_with_duplicates():
    # Test sorting a list with duplicate values
    arr = [4, 2, 5, 2, 3, 4]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_negative_numbers():
    # Test sorting a list with negative numbers
    arr = [-3, -1, -2, 0, 2]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_mixed_numbers():
    # Test sorting a list with positive, negative, and zero
    arr = [0, -1, 3, -2, 2, 1]
    result = await sorter(arr.copy())

# -------------------------
# Edge Test Cases
# -------------------------

@pytest.mark.asyncio
async def test_sorter_all_equal_elements():
    # Test sorting a list where all elements are equal
    arr = [7, 7, 7, 7]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_large_numbers():
    # Test sorting a list with very large integers
    arr = [999999, 123456789, -987654321, 0]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_floats_and_integers():
    # Test sorting a list with floats and integers
    arr = [3.2, 1, 4.5, 2.2, 0]
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_concurrent_calls():
    # Test concurrent execution of sorter with different input lists
    arr1 = [5, 3, 1]
    arr2 = [10, 2, 8, 6]
    arr3 = [0]
    # Run all at once
    results = await asyncio.gather(
        sorter(arr1.copy()),
        sorter(arr2.copy()),
        sorter(arr3.copy())
    )

@pytest.mark.asyncio
async def test_sorter_awaitable_behavior():
    # Test that sorter returns a coroutine and must be awaited
    arr = [3, 2, 1]
    codeflash_output = sorter(arr.copy()); coro = codeflash_output
    result = await coro

@pytest.mark.asyncio
async def test_sorter_cancelled_task():
    # Test cancellation of sorter coroutine
    arr = [4, 3, 2, 1]
    task = asyncio.create_task(sorter(arr.copy()))
    await asyncio.sleep(0.000001)  # Let the sorter start
    task.cancel()
    try:
        await task
    except asyncio.CancelledError:
        # Expected behavior
        return

@pytest.mark.asyncio
async def test_sorter_exception_on_non_list():
    # Test that sorter raises an exception on non-list input
    with pytest.raises(TypeError):
        await sorter("not a list")
    with pytest.raises(TypeError):
        await sorter(None)
    with pytest.raises(TypeError):
        await sorter(123)

@pytest.mark.asyncio
async def test_sorter_list_with_unorderable_types():
    # Test that sorter raises exception on list with unorderable types
    arr = [1, "two", 3]
    with pytest.raises(TypeError):
        await sorter(arr.copy())

# -------------------------
# Large Scale Test Cases
# -------------------------

@pytest.mark.asyncio
async def test_sorter_large_list():
    # Test sorting a large list (but <1000 elements)
    arr = list(range(999, -1, -1))  # 1000 elements, descending
    result = await sorter(arr.copy())

@pytest.mark.asyncio
async def test_sorter_concurrent_large_lists():
    # Test concurrent sorting of multiple large lists
    lists = [list(range(i, i-100, -1)) for i in range(999, 899, -20)]  # 5 lists of 100 elements each
    coros = [sorter(lst.copy()) for lst in lists]
    results = await asyncio.gather(*coros)
    for res in results:
        pass

@pytest.mark.asyncio
async def test_sorter_performance_under_load():
    # Test performance under concurrent load (10 lists of 100 elements)
    lists = [list(range(100, 0, -1)) for _ in range(10)]
    coros = [sorter(lst.copy()) for lst in lists]
    # Set a reasonable timeout to ensure performance (should not take >1 second)
    try:
        results = await asyncio.wait_for(asyncio.gather(*coros), timeout=1.0)
    except asyncio.TimeoutError:
        pytest.fail("sorter took too long under concurrent load")
    for res in results:
        pass
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.

To edit these changes git checkout codeflash/optimize-sorter-mfbuuwpo and push.