[LeetCode] 605. Can Place Flowers

题：https://leetcode.com/problems/can-place-flowers/description/

题目

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:

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.

题目大意

种一朵花，两边都不能有花，求最多可以种多少花。

思路

贪心算法

从左到右位置遍历，若 左右位置都没有花，那么可以种，且将该位置 标志为有花。

class Solution {
    public boolean canPlaceFlowers(int[] flowerbed, int n) {
        int cnt = 0 ; 
        for(int i = 0 ; i < flowerbed.length; i++){
            if(flowerbed[i] == 1)
                continue;
            int pre = i-1>=0?flowerbed[i-1]:0;
            int next = i+1<flowerbed.length?flowerbed[i+1]:0;
            if(pre == 0 && next == 0){
                cnt++;
                flowerbed[i] = 1;
            }
        }
        return cnt>=n?true:false;
    }
}