种花问题（Can Place Flowers）——两朵花不能相邻

1.问题描述

Suppose you have a long flowerbed in which some of the plots are planted and some are not. However, flowers cannot be planted in adjacent plots - they would compete for water and both would die.

Given a flowerbed (represented as an array containing 0 and 1, where 0 means empty and 1 means not empty), and a number n, return if n new flowers can be planted in it without violating the no-adjacent-flowers rule.【假设你有一个很长的花圃，其中有些地是种植的，有些不是。然而，鲜花不能种植在相邻的地块上——它们会争夺水，两者都会死亡。给定一个花坛(表示为包含0和1的数组，其中0表示为空，1表示不为空)和一个数字n，如果可以在不违反无邻接花规则的情况下在花坛中种植n个新花，则返回。】

2.输入

[1,0,0,0,1] 1
[1,0,0,0,1] 2

3.输出

true
false

4.代码

从控制台读取输入，读入的数据为字符串，需要预处理。

用一个mask矩阵记录当前flowerbed的位置是否能种植新的花朵。

每种植一新的花朵，就更新mask

若count>=target print :true

if __name__ == "__main__":

    def update_mask(mask,flowerbed):
        for idx in range(len(flowerbed)):
            if len(flowerbed)==1:
                mask[idx]=False if flowerbed[idx]=='1' else True
            elif len(flowerbed)==2:
                if idx==0 and flowerbed[idx]=='1':
                    mask[idx]=False
                    mask[idx+1]=False
                if idx==1 and flowerbed[idx]=='1':
                    mask[idx-1] = False
                    mask[idx] = False
            elif len(flowerbed) >= 3:
                if idx==0 and flowerbed[idx]=='1':
                    mask[idx]=False
                    mask[idx+1]=False
                elif idx==len(flowerbed)-1 and flowerbed[idx]=='1':
                    mask[idx - 1] = False
                    mask[idx] = False
                elif flowerbed[idx]=='1':
                    mask[idx - 1] = False
                    mask[idx] = False
                    mask[idx+1]=False
        return mask

    while True:
        data = input()
        list_data = data[1:-3]
        target = int(data[-1])
        flowerbed = list_data.split(',')
        mask = [True]*len(flowerbed)
        mask = update_mask(mask, flowerbed)
        # 已经得到了mask
        # 开始插花
        count = 0
        for idx in range(len(mask)):
            if mask[idx]==True:
                flowerbed[idx]='1'
                count += 1
                mask=update_mask(mask,flowerbed)

        if count>=target:
            print('true')
        else:
            print('false')