Problem:
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.
Code:
class Solution {
public:
bool canPlaceFlowers(vector<int>& flowerbed, int n) {
if (n == 0)return true;
//flowerbed为空
if (flowerbed.size() == 0)return false;
//flowerbed只有一个坑
if (flowerbed.size() == 1)
{
return flowerbed[0] == 0;
}
//处理两个特殊的点,即两个边界点
if (flowerbed[0] == 0 && flowerbed[1] == 0) {
flowerbed[0] = 1;
n--;
}
for (int i = 0; i < flowerbed.size() - 1; i++) {
if (flowerbed[i] == 1) {
continue;
}
if (flowerbed[i - 1] == 0 && flowerbed[i + 1] == 0)
{
flowerbed[i] = 1;
n--;
}
}
//最后一个点
if (flowerbed[flowerbed.size() - 2] == 0 && flowerbed[flowerbed.size() - 1] == 0){
flowerbed[flowerbed.size() - 1] = 1;
n--;
}
return n <= 0;//小于等于0表示至少能种n棵树
}
};