调整数组顺序使奇数位于偶数前面

【转】参考：https://blog.youkuaiyun.com/besmarterbestronger/article/details/94960879

题目：

输入一个整数数组，实现一个函数来调整该数组中数字的顺序，使得所有的奇数位于数组的前半部分，所有的偶数位于数组的后半部分，并保证奇数和奇数，偶数和偶数之间的相对位置不变

复习冒泡排序：

def maopao(array):
    for i in range(len(array)):
        for j in range(len(array) - i - 1):
            if array[j] > array[j+1]:
                array[j], array[j+1] = array[j+1], array[j]
    return array

b = maopao([5, 4, 3, 2])
print(b)

# 笨方法，空间换时间把，这里不整那些双指针了
class Solution:
    def reOrderArray(self, array):
        # write code here
        a = []
        b = []
        for i in array:
            if i & 1:
                a.append(i)
            else:
                b.append(i)
        return a + b

复习快速排序（基础版本 + 进阶版）：

def quicksort(array):
    """常规思路，缺点需要开辟新的数组，不能原地排序"""
    if len(array) < 2:
        return array
    else:
        index = 0
        pivot = array[index]
        less = [i for i in array[1:] if i <= pivot]
        great = [i for i in array[1:] if i > pivot]
        return quicksort(less) + [pivot] + quicksort(great)

def partition(array, beg, end):
    """双指针思路, 利用partition原地排序"""
    pivot_index = beg
    pivot = array[pivot_index]

    left = pivot_index + 1
    right = end - 1

    while True:
        while left <= right and array[left] < pivot:
            left += 1

        while right >= left and array[right] >= pivot:
            right -= 1

        if left > right:
            break
        else:
            array[left], array[right] = array[right], array[left]

    array[pivot_index], array[right] = array[right], array[pivot_index]
    return right


def quicksort2(array, beg, end):
    if beg < end:
        pivot = partition(array, beg, end)
        quicksort2(array, beg, pivot)
        quicksort2(array, pivot + 1, end)

def test():

    # seq = list(range(5))
    seq = [1, 3, 2, 4, 0]
    # random.shuffle(seq)
    print("seq = ", seq)
    quicksort2(seq, 0, len(seq))
    print(seq)

if __name__ == "__main__":
    test()

# seq =  [1, 3, 2, 4, 0]
# [0, 1, 2, 3, 4]