1、题目名称
Can Place Flowers(花坛插花)
2、题目地址
3、题目内容
英文:
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 = 1Output: True
Example 2:
Input: flowerbed = [1,0,0,0,1], n = 2Output: 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.
中文:
有一个花坛,用数组表示,0表示当前位置还没有花,1表示当前位置有一朵花,现在你手上有n朵花,要把这n朵花插到花坛中去。但要注意,任意两朵花不能相邻。
4、解题方法
先要考虑极端的情况,即花坛中只有一个空位置时,手中恰有一朵花,是可以插进去的。
在向花坛中插花时,先处理花坛的首尾,再通过循环将剩余的花插入到合适的空位置。
/** * LeetCode 605 - Can Place Flowers * @文件名称 Solution.java * @文件作者 Tsybius2014 * @创建时间 2017年9月25日17:15:39 */class Solution { /** * 花坛插花 - 检测花坛内是否还能种植n朵花 * @param flowerbed * @param n * @return */ public boolean canPlaceFlowers(int[] flowerbed, int n) { //没有多余的花要插,一定是满足条件的 if (n <= 0) { return true; } //只有一个空位的情况,直接判断 if (flowerbed.length == 1) { if (flowerbed[0] == 0) { if (n <= 1) { return true; } else { return false; } } else { if (n <= 0) { return true; } else { return false; } } } //先顾首尾 if (flowerbed.length >= 2) { if (flowerbed[0] == 0 && flowerbed[1] == 0) { flowerbed[0] = 1; n--; if (n == 0) { return true; } } if (flowerbed[flowerbed.length - 1] == 0 && flowerbed[flowerbed.length - 2] == 0) { flowerbed[flowerbed.length - 1] = 1; n--; if (n == 0) { return true; } } } //只有左右都无花的情况才能插入一朵花 for (int i = 1; i < flowerbed.length - 1; i++) { if (flowerbed[i - 1] == 0 && flowerbed[i] == 0 && flowerbed[i + 1] == 0) { flowerbed[i] = 1; n--; if (n == 0) { return true; } } } return false; }}
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