// Time:  O(n)
// Space: O(1)

class Solution {
public:
    bool canPlaceFlowers(vector<int>& flowerbed, int n) {
        for (int i = 0; i < flowerbed.size(); ++i) {
            if (flowerbed[i] == 0 && (i == 0 || flowerbed[i - 1] == 0) &&
                (i == flowerbed.size() - 1 || flowerbed[i + 1] == 0)) {
                flowerbed[i] = 1;
                --n;
            }
            if (n <= 0) {
                return true;
            }
        }
        return false;
    }
};