21

def ReOrderOddEven(li):
    '''思路：1.如果low索引元素为奇数就+1.知道找到为偶数的下标；2.如果high为偶数 就-1 直到找到基数的下标3，交换的条件是：左边为偶数，右边为基数'''
    low = 0
    high = len(li) - 1

    while low < high:
        if li[low] % 2 == 0 and li[high] % 2 == 1:
            li[low], li[high] = li[high], li[low]
        if li[low] % 2 == 1:
            low += 1
        if li[high] % 2 == 0:
            high -= 1

    return li


print(ReOrderOddEven([1, 1, 2, 2, 3, 3, 5]))