Can Place Flowers

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.

1.The input array won't violate no-adjacent-flowers rule. 2.The input array size is in the range of [1, 20000]. 3.n is a non-negative integer which won't exceed the input array size.

遍历数组，check他，他前一个 和后一个 同时注意边界问题

time o(n). space o(1)

public class Solution {
    /**
     * @param flowerbed: an array
     * @param n: an Integer
     * @return: if n new flowers can be planted in it without violating the no-adjacent-flowers rule
     */
    public boolean canPlaceFlowers(int[] flowerbed, int n) {
        // Write your code here
        
        if(flowerbed == null || flowerbed.length == 0 || n >= flowerbed.length){
            return false;
        }
        
        int count = 0;
        
        for (int i = 0; i < flowerbed.length ;i++ ){
            if(flowerbed[i] == 0 && (i == 0 || flowerbed[i-1] == 0) 
                && (i == flowerbed.length -1 || flowerbed[i+1] == 0)
            ){
                flowerbed[i] = 1;
                count++;
            }
            
            if(count >= n){
                return true;
            }
        } 
        
        return false;
        
    }
}