選擇排序-python

def selection_sort(arr):
    """
    選擇排序
    :param arr: 待排序數組
    :return:
    """
    length = len(arr)
    for x in range(length):
        min_index = x
        # 選取最小的下標
        for y in range(x + 1, length):
            if arr[min_index] > arr[y]:
                min_index = y
        # 交換
        arr[x], arr[min_index] = arr[min_index], arr[x]


if __name__ == '__main__':
    arr = [20, -1, 2, 11, 8, 100, 4, 10, 23, 6, 21]
    selection_sort(arr)
    print(arr)