[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:

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.

思路： 先简单实现，后续在优化。

public class Solution {
public boolean canPlaceFlowers(int[] flowerbed, int n) {
if(flowerbed==null || flowerbed.length ==0) {
return false;
}
if(n==0) {
return true;
}
int len = flowerbed.length;
if(len==1) {
return flowerbed[0]==0;
}

int count=0;
for(int i=0;i<len;i++) {
if(flowerbed[i]==0) {
if(i==0){
if(flowerbed[i+1]==0) {
flowerbed[i]=1;
count++;
if(count==n) {
return true;
}
}
} else if(i==len-1){
if(flowerbed[i-1]==0) {
flowerbed[i]=1;
count++;
if(count==n) {
return true;
}
}
} else if(flowerbed[i-1]==0 && flowerbed[i+1]==0) {
flowerbed[i]=1;
count++;
if(count==n) {
return true;
}
}
}
}
return false;
}
}