CanPlaceFlowers.java

/*
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.

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

runs in 6ms - faster than 85% of submissions
*/

class Solution {
    public boolean canPlaceFlowers(int[] flowerbed, int n) {
        if(n == 0) return true;
        if(flowerbed.length == 0) return false;
        if(flowerbed.length == 1) {
            if(flowerbed[0] == 1) return false;
            else return true;
        }
        for(int i = 0; i < flowerbed.length; i ++) {
            if(n == 0) return true;
            else if(i == 0) {
                if(flowerbed[i] == 0 && flowerbed[i+1] == 0) {
                    flowerbed[i] = 1;
                    n --;
                }
            }
            else if(i == flowerbed.length - 1) {
                if(flowerbed[i] == 0 && flowerbed[i-1] == 0) {
                    flowerbed[i] = 1;
                    n --;
                }
            }
            else {
                if(flowerbed[i] == 0 && flowerbed[i-1] == 0 && flowerbed[i+1] == 0) {
                    flowerbed[i] = 1;
                    n --;
                }
            }
        }
        if(n == 0) return true;
        return false;
    }
}