palindromic-subarray-sum

java

python3

python

javascript

typescript

csharp

golang

kotlin

swift

rust

ruby

dart

scala

elixir

erlang

racket

bash

mysql

mssql

postgresql

oraclesql

pythondata

Algorithms

You are given an integer array <code>nums</code>.

Return the maximum possible sum of a subarray of <code>nums</code> that is a palindrome.

&nbsp;
Example 1:

<div class="example-block">
Input: nums = [10,10]

Output: 20

Explanation:

The whole array <code>[10,10]</code> is a palindrome. Therefore, the maximum sum is <code>10 + 10 = 20</code>.
</div>

Example 2:

<div class="example-block">
Input: nums = [1,2,3,2,1,5,6]

Output: 9

Explanation:

The contiguous subarray <code>[1,2,3,2,1]</code> is a palindrome. Its sum is <code>1 + 2 + 3 + 2 + 1 = 9</code> and it is the maximum sum.
</div>

Example 3:

<div class="example-block">
Input: nums = [7,1,2,1,7,3,4,3,4]

Output: 18

Explanation:

The contiguous subarray <code>[7,1,2,1,7]</code> is a palindrome. Its sum is <code>7 + 1 + 2 + 1 + 7 = 18</code> and it is the maximum sum.
</div>

Example 4:

<div class="example-block">
Input: nums = [1,2,3,4,5]

Output: 5

Explanation:

No subarray with length greater than 1 is a palindrome. The largest element in the array is 5. Therefore, the answer is 5.
</div>

Example 5:

<div class="example-block">
Input: nums = [1000]

Output: 1000

Explanation:

The subarray with only one element is a palindrome. Therefore, the answer is 1000.
</div>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= nums.length &lt;= 105</code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10​​​​​​​9</code></li>
</ul>