跳格子
class Solution {
public:
bool canPlaceFlowers(vector<int>& flowerbed, int n) {
for(int i = 0;i < flowerbed.size() && n > 0;){
if(flowerbed[i] == 1) i+=2;
else if(i == flowerbed.size()-1 || flowerbed[i+1] == 0){
n--;
i+=2;
}
else i+=3;
}
return n<=0;
}
};