0605. Can Place Flowers

https://leetcode.com/problems/can-place-flowers

Description

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 if n new flowers can be planted in the flowerbed without violating the no-adjacent-flowers rule.

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

ac

class Solution {
    public boolean canPlaceFlowers(int[] flowerbed, int n) {
        // edge cases
        if (n > (flowerbed.length + 1) / 2) return false;

        // plant
        for (int i = 0; i < flowerbed.length; i++) {
            if (n == 0) return true;
            if (flowerbed[i] == 1) continue;

            int prev = i == 0 ? 0 : flowerbed[i-1];
            int next = i == flowerbed.length - 1 ? 0 : flowerbed[i+1];

            if (prev == 0 && next == 0) {
                flowerbed[i] = 1;
                n--;
            }
        }

        return n == 0;
    }
}

/*
lots of disgusting edge cases
*/