flatten-deeply-nested-array

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JavaScript

Given a&nbsp;multi-dimensional array&nbsp;<code>arr</code>&nbsp;and a depth <code>n</code>, return&nbsp;a&nbsp;flattened&nbsp;version of that array.

A multi-dimensional&nbsp;array is a recursive data structure that contains integers or other&nbsp;multi-dimensional&nbsp;arrays.

A&nbsp;flattened&nbsp;array is a version of that array with some or all of the sub-arrays removed and replaced with the actual elements in that sub-array. This flattening operation should only be done if the current depth of nesting&nbsp;is less&nbsp;than&nbsp;<code>n</code>. The depth of the elements in the first array are considered to be&nbsp;<code>0</code>.

Please solve it without the built-in&nbsp;<code>Array.flat</code> method.

&nbsp;
Example 1:

<pre>
Input
arr = [1, 2, 3, [4, 5, 6], [7, 8, [9, 10, 11], 12], [13, 14, 15]]
n = 0
Output
[1, 2, 3, [4, 5, 6], [7, 8, [9, 10, 11], 12], [13, 14, 15]]

Explanation
Passing a depth of n=0 will always result in the original array. This is because the smallest possible depth of a subarray (0) is not less than n=0. Thus, no subarray should be flattened. </pre>

Example 2:

<pre>
Input
arr = [1, 2, 3, [4, 5, 6], [7, 8, [9, 10, 11], 12], [13, 14, 15]]
n = 1
Output
[1, 2, 3, 4, 5, 6, 7, 8, [9, 10, 11], 12, 13, 14, 15]

Explanation
The subarrays starting with 4, 7, and 13 are all flattened. This is because their depth of 0 is less than 1. However [9, 10, 11] remains unflattened because its depth is 1.</pre>

Example 3:

<pre>
Input
arr = [[1, 2, 3], [4, 5, 6], [7, 8, [9, 10, 11], 12], [13, 14, 15]]
n = 2
Output
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

Explanation
The maximum depth of any subarray is 1. Thus, all of them are flattened.</pre>

&nbsp;
Constraints:

<ul>
	<li><code>0 &lt;= count of numbers in arr &lt;=&nbsp;105</code></li>
	<li><code>0 &lt;= count of subarrays in arr &lt;=&nbsp;105</code></li>
	<li><code>maxDepth &lt;= 1000</code></li>
	<li><code>-1000 &lt;= each number &lt;= 1000</code></li>
	<li><code>0 &lt;= n &lt;= 1000</code></li>
</ul>

foobar

Flatten Deeply Nested Array

JSON Deep Equal

json-deep-equal

完全相等的 JSON 字符串

Convert Object to JSON String

convert-object-to-json-string

将对象转换为 JSON 字符串

Nested Array Generator

nested-array-generator

嵌套数组生成器

请你编写一个函数，它接收一个&nbsp;多维数组&nbsp;<code>arr</code> 和它的深度 <code>n</code> ，并返回该数组的&nbsp;扁平化&nbsp;后的结果。

多维数组&nbsp;是一种包含整数或其他&nbsp;多维数组&nbsp;的递归数据结构。

数组 扁平化 是对数组的一种操作，定义是将原数组部分或全部子数组删除，并替换为该子数组中的实际元素。只有当嵌套的数组深度大于 <code>n</code> 时，才应该执行扁平化操作。第一层数组中元素的深度被认为是 0。

请在没有使用内置方法&nbsp;<code>Array.flat</code> 的前提下解决这个问题。

&nbsp;

示例 1：

<pre>
输入
arr = [1, 2, 3, [4, 5, 6], [7, 8, [9, 10, 11], 12], [13, 14, 15]]
n = 0
输出
[1, 2, 3, [4, 5, 6], [7, 8, [9, 10, 11], 12], [13, 14, 15]]

解释
传递深度 n=0 的多维数组将始终得到原始数组。这是因为 子数组(0) 的最小可能的深度不小于 n=0 。因此，任何子数组都不应该被平面化。
</pre>

示例 2：

<pre>
输入
arr = [1, 2, 3, [4, 5, 6], [7, 8, [9, 10, 11], 12], [13, 14, 15]]
n = 1
输出
[1, 2, 3, 4, 5, 6, 7, 8, [9, 10, 11], 12, 13, 14, 15]

解释
以 4 、7 和 13 开头的子数组都被扁平化了，这是因为它们的深度为 0 ， 而 0 小于 1 。然而 [9,10,11] 其深度为 1 ，所以未被扁平化。</pre>

示例 3：

<pre>
输入
arr = [[1, 2, 3], [4, 5, 6], [7, 8, [9, 10, 11], 12], [13, 14, 15]]
n = 2
输出
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

解释
所有子数组的最大深度都为 1 。因此，它们都被扁平化了。</pre>

&nbsp;

提示：

<ul>
	<li><code>0 &lt;= arr 的元素个数&nbsp;&lt;=&nbsp;105</code></li>
	<li><code>0 &lt;= arr 的子数组个数&nbsp;&lt;=&nbsp;105</code></li>
	<li><code>maxDepth &lt;= 1000</code></li>
	<li><code>-1000 &lt;= each number &lt;= 1000</code></li>
	<li><code>0 &lt;= n &lt;= 1000</code></li>
</ul>