sorting.py

import random
import time


def bubble_sort(arr):
    arr = arr[:]
    n = len(arr)
    for i in range(n):
        swapped = False
        for j in range(0, n - i - 1):
            if arr[j] > arr[j + 1]:
                arr[j], arr[j + 1] = arr[j + 1], arr[j]
                swapped = True
        if not swapped:
            break
    return arr


def selection_sort(arr):
    arr = arr[:]
    n = len(arr)
    for i in range(n):
        min_idx = i
        for j in range(i + 1, n):
            if arr[j] < arr[min_idx]:
                min_idx = j
        arr[i], arr[min_idx] = arr[min_idx], arr[i]
    return arr


def insertion_sort(arr):
    arr = arr[:]
    for i in range(1, len(arr)):
        key = arr[i]
        j = i - 1
        while j >= 0 and arr[j] > key:
            arr[j + 1] = arr[j]
            j -= 1
        arr[j + 1] = key
    return arr


def merge_sort(arr):
    if len(arr) <= 1:
        return arr[:]
    mid = len(arr) // 2
    left = merge_sort(arr[:mid])
    right = merge_sort(arr[mid:])
    return _merge(left, right)


def _merge(left, right):
    result = []
    i = j = 0
    while i < len(left) and j < len(right):
        if left[i] <= right[j]:
            result.append(left[i])
            i += 1
        else:
            result.append(right[j])
            j += 1
    result.extend(left[i:])
    result.extend(right[j:])
    return result


def quick_sort(arr):
    if len(arr) <= 1:
        return arr[:]
    pivot = arr[len(arr) // 2]
    left = [x for x in arr if x < pivot]
    middle = [x for x in arr if x == pivot]
    right = [x for x in arr if x > pivot]
    return quick_sort(left) + middle + quick_sort(right)


def heap_sort(arr):
    arr = arr[:]
    n = len(arr)

    for i in range(n // 2 - 1, -1, -1):
        _heapify(arr, n, i)

    for i in range(n - 1, 0, -1):
        arr[0], arr[i] = arr[i], arr[0]
        _heapify(arr, i, 0)

    return arr


def _heapify(arr, n, i):
    largest = i
    left = 2 * i + 1
    right = 2 * i + 2

    if left < n and arr[left] > arr[largest]:
        largest = left
    if right < n and arr[right] > arr[largest]:
        largest = right

    if largest != i:
        arr[i], arr[largest] = arr[largest], arr[i]
        _heapify(arr, n, largest)


def counting_sort(arr):
    if not arr:
        return []
    min_val, max_val = min(arr), max(arr)
    count = [0] * (max_val - min_val + 1)
    for x in arr:
        count[x - min_val] += 1
    result = []
    for i, c in enumerate(count):
        result.extend([i + min_val] * c)
    return result


def radix_sort(arr):
    if not arr:
        return []
    arr = arr[:]
    max_val = max(arr)
    exp = 1
    while max_val // exp > 0:
        arr = _counting_sort_by_digit(arr, exp)
        exp *= 10
    return arr


def _counting_sort_by_digit(arr, exp):
    n = len(arr)
    output = [0] * n
    count = [0] * 10

    for x in arr:
        index = (x // exp) % 10
        count[index] += 1

    for i in range(1, 10):
        count[i] += count[i - 1]

    for i in range(n - 1, -1, -1):
        index = (arr[i] // exp) % 10
        output[count[index] - 1] = arr[i]
        count[index] -= 1

    return output


def benchmark_sorts(size=5000):
    arr = [random.randint(1, 10000) for _ in range(size)]

    algorithms = {
        "Bubble Sort": bubble_sort,
        "Selection Sort": selection_sort,
        "Insertion Sort": insertion_sort,
        "Merge Sort": merge_sort,
        "Quick Sort": quick_sort,
        "Heap Sort": heap_sort,
        "Counting Sort": counting_sort,
        "Radix Sort": radix_sort,
    }

    print(f"배열 크기: {size}")
    print("-" * 40)

    results = {}
    for name, func in algorithms.items():
        start = time.perf_counter()
        sorted_arr = func(arr)
        elapsed = time.perf_counter() - start
        results[name] = elapsed
        assert sorted_arr == sorted(arr), f"{name} 정렬 실패!"
        print(f"  {name:<20} {elapsed:.4f}초")

    print("-" * 40)
    fastest = min(results, key=results.get)
    print(f"  가장 빠른 알고리즘: {fastest} ({results[fastest]:.4f}초)")


if __name__ == "__main__":
    benchmark_sorts()