<p>You are given an integer array <code>nums</code>. You want to maximize the number of points you get by performing the following operation any number of times:</p>

<ul>
	<li>Pick any <code>nums[i]</code> and delete it to earn <code>nums[i]</code> points. Afterwards, you must delete <b>every</b> element equal to <code>nums[i] - 1</code> and <strong>every</strong> element equal to <code>nums[i] + 1</code>.</li>
</ul>

<p>Return <em>the <strong>maximum number of points</strong> you can earn by applying the above operation some number of times</em>.</p>

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

<pre>
<strong>Input:</strong> nums = [3,4,2]
<strong>Output:</strong> 6
<strong>Explanation:</strong> You can perform the following operations:
- Delete 4 to earn 4 points. Consequently, 3 is also deleted. nums = [2].
- Delete 2 to earn 2 points. nums = [].
You earn a total of 6 points.
</pre>

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

<pre>
<strong>Input:</strong> nums = [2,2,3,3,3,4]
<strong>Output:</strong> 9
<strong>Explanation:</strong> You can perform the following operations:
- Delete a 3 to earn 3 points. All 2&#39;s and 4&#39;s are also deleted. nums = [3,3].
- Delete a 3 again to earn 3 points. nums = [3].
- Delete a 3 once more to earn 3 points. nums = [].
You earn a total of 9 points.</pre>

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

<ul>
	<li><code>1 &lt;= nums.length &lt;= 2 * 10<sup>4</sup></code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>4</sup></code></li>
</ul>

class Solution {
public:
    int getAns(vector<pair<int, int>>& vec, int idx, vector<int>& dp)
    {
        int n = vec.size();

        if(idx>=n)
        {
            return 0;
        }

        if(dp[idx]!=-1)
        {
            return dp[idx];
        }

        // take
        int take = vec[idx].first * vec[idx].second;
        
        if(idx+1<n && (vec[idx+1].first==vec[idx].first+1))
        {
            take+=getAns(vec, idx+2, dp);
        }
        else
        {
            take+=getAns(vec, idx+1, dp);
        }

        // notTake

        int notTake = getAns(vec, idx+1, dp);

        return dp[idx]=max(take, notTake);
    }

    int deleteAndEarn(vector<int>& nums) {
        
        map<int, int> mp;


        for(int i: nums)
        {
            mp[i]++;
        }

        vector<pair<int, int>> vec;

        for(auto i: mp)
        {
            vec.push_back({i.first, i.second});
        }
        vector<int> dp(vec.size()+1, -1);

        return getAns(vec, 0, dp);
    }
};
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