605. 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.

给出一个序列代表花床，其中1表示种着有花，0代表没有，规则是种着花的相邻位置不能种花，问还能不能种下n朵花。在程序中模拟种花的过程，遍历序列，在符合规则的位置种下花（也就是令相应位置的值为1），种下一朵花的过程中令n减一，最后如果n小于等于0的话就说明能种下n朵，返回true。

代码：

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