605. Can Place Flowers

Problem

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 * 10^4

• flowerbed[i] is 0 or 1.

• There are no two adjacent flowers in flowerbed.

• 0 <= n <= flowerbed.length

Solution (Java)

class Solution {
    public boolean canPlaceFlowers(int[] flowerbed, int n) {
        for (int i = 0; i < flowerbed.length; i++) {
            if (flowerbed[i] == 0 && n > 0) {
                boolean left = i == 0 || flowerbed[i - 1] == 0;
                boolean right = i == flowerbed.length - 1 || flowerbed[i + 1] == 0;
                if (left && right) {
                    flowerbed[i] = 1;
                    n--;
                }
            }
            if (n == 0) {
                break;
            }
        }
        return n == 0;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).