[leetcode-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:

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

思路：

看是否有连续三个0,注意最左边边界和最右边边界。

bool canPlaceFlowers(vector<int>& flowerbed, int n)
{
  int len = flowerbed.size();
  if(len== && flowerbed[]== && n<=)return true;  

  int can =;
  for(int i=;i<len;i++)
  {
     if(flowerbed[i]== && i->= && i+<len && flowerbed[i-]==&& flowerbed[i+]==)
     {
       can++;
       flowerbed[i]=;
     }
     if(i==&& flowerbed[] ==  && flowerbed[]==)
     {
       can++;
       flowerbed[]=;
    }
    if(i==len-&& flowerbed[len-] ==  && flowerbed[len-]==)
     {
       can++;
       flowerbed[len-]=;
    }
  }
  if(can>=n)return true;
  return false;
}