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.
Given an integer array flowerbed containing 0's and 1's, where 0 means empty and 1 means not empty, and an integer n, return trueifnnew flowers can be planted in theflowerbedwithout violating the no-adjacent-flowers rule andfalseotherwise.
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
Constraints:
1 <= flowerbed.length <= 2 * 104
flowerbed[i] is 0 or 1.
There are no two adjacent flowers in flowerbed.
0 <= n <= flowerbed.length
Solutions
Solution 1: Greedy
We directly traverse the array $flowerbed$. For each position $i$, if $flowerbed[i]=0$ and its adjacent positions on the left and right are also $0$, then we can plant a flower at this position. Otherwise, we cannot. Finally, we count the number of flowers that can be planted. If it is not less than $n$, we return $true$, otherwise we return $false$.
The time complexity is $O(n)$, where $n$ is the length of the array $flowerbed$. We only need to traverse the array once. The space complexity is $O(1)$.