算法: 快排

Posted 2021-01-28 gyh412724

快排:

data = [2, 5, 1, 6, 3, 9, 7]
def quick_sort(data, left, right):
    if left < right:
        # 1 确定中间数的位置, 求出中间数的索引
        mid = partition(data, left, right)
        print(mid)
        # 2 对剩余的两部分排序, 采用递归
        quick_sort(data, left, mid - 1)
        quick_sort(data, mid + 1, right)
    print(data)
def partition(data, left, right):
    tmp = data[left]
    while left < right:
        # 加left < right的原因: 由于跳不出循环, 所以加上条件, 要么是left +1 , 或者是right - 1. 
        while tmp < data[right] and left < right:
            right = right - 1
        data[left] = data[right]
        while tmp > data[left] and left < right:
            left = left + 1
        data[right] = data[left]
    data[left] = tmp
    return left
quick_sort(data, 0, len(data) - 1)

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