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.

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

思路：贪心

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