[leetcode] 605. Can Place Flowers _ Algorithm Problem Solve for python

1. Problem

605. Can Place Flowers

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.

Given an integer array flowerbed containing 0’s and 1’s, where 0 means empty and 1 means not empty, and an integer n, return true if n new flowers can be planted in the flowerbed without violating the no-adjacent-flowers rule and false otherwise.

Example 1:

Input: flowerbed = [1,0,0,0,1], n = 1
Output: true

Example 2:

Input: flowerbed = [1,0,0,0,1], n = 2
Output: false

Constraints:

• 1 <= flowerbed.length <= 2 * 104
• flowerbed[i] is 0 or 1.
• There are no two adjacent flowers in flowerbed.
• 0 <= n <= flowerbed.length

2. Solution

I solved this problem like this.

• Complexity
  • Time complexity : O(N)
  • Space complexity : O(1)
• Step
  • Make list to string
  • Split string to ‘1’
  • count 0’s num
    • one 0 string : (len(x) + 1)//2
    • side 0 string : (len(x))//2
    • other 0 string : (len(x) - 1)//2

class Solution:
    def canPlaceFlowers(self, flowerbed: List[int], n: int) -> bool:
        zero_areas = ''.join(list(map(str, flowerbed))).split('1')
        possible = 0
        for i, x in enumerate(zero_areas):
            if len(zero_areas) == 1:
                possible += (len(x) + 1) // 2
            elif i == 0 or i == len(zero_areas) - 1:
                possible += (len(x)) // 2
            else:
                possible += (len(x) - 1) // 2
            
        return possible >= n