# 1140. Stone Game II

<https://leetcode.com/problems/stone-game-ii>

## Description

Alice and Bob continue their games with piles of stones.  There are a number of piles **arranged in a row**, and each pile has a positive integer number of stones `piles[i]`.  The objective of the game is to end with the most stones.&#x20;

Alice and Bob take turns, with Alice starting first.  Initially, `M = 1`.

On each player's turn, that player can take **all the stones** in the **first** `X` remaining piles, where `1 <= X <= 2M`.  Then, we set `M = max(M, X)`.

The game continues until all the stones have been taken.

Assuming Alice and Bob play optimally, return the maximum number of stones Alice can get.

**Example 1:**

```
**Input:** piles = [2,7,9,4,4]
**Output:** 10
**Explanation:**  If Alice takes one pile at the beginning, Bob takes two piles, then Alice takes 2 piles again. Alice can get 2 + 4 + 4 = 10 piles in total. If Alice takes two piles at the beginning, then Bob can take all three piles left. In this case, Alice get 2 + 7 = 9 piles in total. So we return 10 since it's larger. 
```

**Example 2:**

```
**Input:** piles = [1,2,3,4,5,100]
**Output:** 104
```

**Constraints:**

* `1 <= piles.length <= 100`
* `1 <= piles[i] <= 104`

## ac

```java
```