can-PlaceFlowers*

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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


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class Solution {
public:
    bool canPlaceFlowers(vector<int>& flowerbed, int n) {
        int res = 0, l = -2, r = 0;
        while(r < flowerbed.size()){
            if(flowerbed[r] == 1){
                res += (r - l - 2) / 2;
                l = r;
            }
            r++;
        }
        res += (r - l - 1) / 2;
        return res >= n;
    }
};