贪心

class Solution {
public:
    bool canPlaceFlowers(vector<int>& flowerbed, int n) {
        int m = flowerbed.size();
        int pre = -1;
        for(int i=0;i<m;i++){
            //寻找区间
            if(flowerbed[i]==1){
                if(pre<0){
                    n-=i/2;
                }else{
                    n-=(i-pre-2)/2;
                }
                pre = i;
            }
        }
        if(pre<0){
            n-=(m+1)/2;
        }else{
            n-=(m-pre-1)/2;
        }
        return n<=0;

    }
};