<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:

    bool result;
    int target;
    unordered_map<int,unordered_map<int,bool>> dp;

    bool helper(vector<int> & nums, int sum, int idx){
        if(idx>=nums.size() or sum>target){
            dp[sum][idx]=false;
            return false;
        }
        
        if(sum==target){
            result=true;
            dp[sum][idx]=true;
            return true;
        }

        if(dp.count(sum) && dp[sum].count(idx))
            return dp[sum][idx];
        
        dp[sum][idx] = helper(nums,sum+nums[idx],idx+1) || helper(nums,sum,idx+1);
        return dp[sum][idx];
    }

    

    bool canPartition(vector<int>& nums) {
        int totalSum=0;
        result=false;
        for(auto num: nums)
            totalSum+=num;

        if(totalSum%2==1)
            return false;
        
        if(nums.size()<=1)
            return false;
        
        target=totalSum/2;
        
        helper(nums,0,0);
        return result;

    }
};
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