<p>Alice and Bob continue their games with piles of stones. There are a number of piles <strong>arranged in a row</strong>, and each pile has a positive integer number of stones <code>piles[i]</code>. The objective of the game is to end with the most stones.</p>

<p>Alice and Bob take turns, with Alice starting first.</p>

<p>On each player&#39;s turn, that player can take <strong>all the stones</strong> in the <strong>first</strong> <code>X</code> remaining piles, where <code>1 &lt;= X &lt;= 2M</code>. Then, we set <code>M = max(M, X)</code>. Initially, M = 1.</p>

<p>The game continues until all the stones have been taken.</p>

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

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">piles = [2,7,9,4,4]</span></p>

<p><strong>Output:</strong> <span class="example-io">10</span></p>

<p><strong>Explanation:</strong></p>

<ul>
	<li>If Alice takes one pile at the beginning, Bob takes two piles, then Alice takes 2 piles again. Alice can get <code>2 + 4 + 4 = 10</code> stones in total.</li>
	<li>If Alice takes two piles at the beginning, then Bob can take all three piles left. In this case, Alice get <code>2 + 7 = 9</code> stones in total.</li>
</ul>

<p>So we return 10 since it&#39;s larger.</p>
</div>

<p><strong class="example">Example 2:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">piles = [1,2,3,4,5,100]</span></p>

<p><strong>Output:</strong> <span class="example-io">104</span></p>
</div>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= piles.length &lt;= 100</code></li>
	<li><code>1 &lt;= piles[i]&nbsp;&lt;= 10<sup>4</sup></code></li>
</ul>

class Solution {
    unordered_map<int, unordered_map<int, pair<int, int>>> m1;
    unordered_map<int, unordered_map<int, pair<int, int>>> m2;
    // unordered_map<int, unordered_map<bool, unordered_map<int, pair<int, int>>>>> m;
    pair<int, int> helper(vector<int>& piles, int idx, bool isAlice, int m)
    {
        
        if (isAlice)
        {
            if (m1.find(idx) != m1.end() && m1[idx].find(m) != m1[idx].end())
            {
                return m1[idx][m];
            }

            if (2 * m >= piles.size() - idx)
            {
                int sum = 0;
                for (int i = idx; i < piles.size(); i++)
                {
                    sum += piles[i];
                }

                return m1[idx][m] = {sum, 0};
            }

            int curIdx = idx;
            int sum = 0;
            int maxA = 0;
            int bestB = 0;

            for (int x = 1; x <= 2 * m; x++)
            {
                sum += piles[curIdx];
                auto [a, b] = helper(piles, curIdx + 1, 0, max(m, x));
                if (sum + a > maxA)
                {
                    maxA = sum + a;
                    bestB = b;
                }
                curIdx++;
            }

            return m1[idx][m] = {maxA, bestB};

        }
        else
        {
            if (m2.find(idx) != m2.end() && m2[idx].find(m) != m2[idx].end())
            {
                return m2[idx][m];
            }

            if (2 * m >= piles.size() - idx)
            {
                int sum = 0;
                for (int i = idx; i < piles.size(); i++)
                {
                    sum += piles[i];
                }

                return m2[idx][m] = {0, sum};
            }

            int curIdx = idx;
            int sum = 0;
            int maxB = 0;
            int bestA = 0;

            for (int x = 1; x <= 2 * m; x++)
            {
                sum += piles[curIdx];
                auto [a, b] = helper(piles, curIdx + 1, 1, max(m, x));
                if (sum + b > maxB)
                {
                    maxB = sum + b;
                    bestA = a;
                }
                curIdx++;
            }

            return m2[idx][m] = {bestA, maxB};
        }
    }
public:
    int stoneGameII(vector<int>& piles)
    {
        auto [a, b] = helper(piles, 0, 1, 1);
        return a;
    }
};
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