<p>Given an integer array <code>nums</code>, return <code>true</code> <em>if you can partition the array into two subsets such that the sum of the elements in both subsets is equal or </em><code>false</code><em> otherwise</em>.</p>

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

<pre>
<strong>Input:</strong> nums = [1,5,11,5]
<strong>Output:</strong> true
<strong>Explanation:</strong> The array can be partitioned as [1, 5, 5] and [11].
</pre>

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

<pre>
<strong>Input:</strong> nums = [1,2,3,5]
<strong>Output:</strong> false
<strong>Explanation:</strong> The array cannot be partitioned into equal sum subsets.
</pre>

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

<ul>
	<li><code>1 &lt;= nums.length &lt;= 200</code></li>
	<li><code>1 &lt;= nums[i] &lt;= 100</code></li>
</ul>

class Solution {
public:

    int helper(int index,vector<int>& nums,int sum,int target,vector<vector<int>> &dp)
    {   
        if(sum>target || index==nums.size())
        {
            return 0;
        }
        if(sum==target)
        {
            return 1;
        }
        if(dp[index][sum]!=-1) return dp[index][sum];
        if(nums[index]>target)
        {
            return dp[index][sum]=0;
        }

        int a=(helper(index+1,nums,sum+nums[index],target,dp));
        int b=(helper(index+1,nums,sum,target,dp));
        return dp[index][sum]=a|b;

    }


    bool canPartition(vector<int>& nums) {
        int cnt=0;
        for(int i=0;i<nums.size();i++)
        {
            cnt+=nums[i];
        }

        sort(nums.begin(),nums.end());

        vector<vector<int>> dp(nums.size()+5,vector<int>(cnt/2+1,-1));

        if(cnt%2!=0)
        {
            return false;
        }
        else
        {
            if(helper(0,nums,0,cnt/2,dp)==1) return true; else return false;
        }
    }
};
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