# # 605. Can Place Flowers

[LeetCode](https://leetcode.com/problems/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.

input: arr = [1,0,0, ...]  1 代表有種花 0 代表沒種花, n 代表新花數量
output: 回傳心花是否可以種完

關鍵是不能種相鄰的花 
```

```
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.

/**
 * @param {number[]} flowerbed
 * @param {number} n
 * @return {boolean}
 */
var canPlaceFlowers = function(flowerbed, n) {}
```

### Edge Case

* \[0], \[0, 1] 之類邊界值

### 怎麼解

其實很單純我卻想很久邊界值怎麼處理，其實只要判斷前後跟自己是不是 1 ，都是就跳過，不是就代表可以種花

### Code

```
var canPlaceFlowers = function(flowerbed, n) {
let len = flowerbed.length;
 let plotsNums = 0;
 for(let i=0; i<len; i+=1){
  
   if(flowerbed[i]===1 || flowerbed[i+1] ===1 || flowerbed[i-1] ===1){
    // do nothing
   }else{
    plotsNums++;
    flowerbed[i] = 1;
   }

 }
 return plotsNums >= n
};
faster than 60.20%
```

### 如何改進

後來看到一個更容易理解就是前後都加 0&#x20;

```
var canPlaceFlowers = function(flowerbed, n) {
    flowerbed.unshift(0);
    flowerbed.push(0);
    for(let i=1;i<flowerbed.length;i++) {
        if(flowerbed[i]===0&&flowerbed[i-1]===0&&flowerbed[i+1]===0) {
            n--;
            flowerbed[i]=1;
        }
    }
    return n<=0;
};
// faster than 90.20%
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://hannahpun.gitbook.io/leetcode-note/array/605.-can-place-flowers.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.