<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 canPartition(vector<int>& nums) {
        int sum = 0;
        for(auto n:nums) {
            sum += n;
        }
        if((sum%2)==1) return false;

        unordered_set<int> dp;
        dp.insert(0);
        int target = sum/2;

        for(int i=nums.size()-1; i>=0 ; i--) {
            unordered_set<int> newDp = dp;
            for(auto d : newDp) {
                if((d + nums[i]) == target) return true;
                dp.insert(d+nums[i]);
            }
        }
        return dp.contains(target);
        
    }
};
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