<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:
    def canPartition(self, nums: List[int]) -> bool:
        visited = {}
        return self.helper(0, 0, nums, visited)
    
    def helper(self, first, second, nums, visited):
        if not nums:
            return first == second
        elif (first, second) in visited:
            return visited[(first, second)]
        elif (second, first) in visited:
            return visited[(second, first)]
        
        result = self.helper(first + nums[0], second, nums[1:], visited) or self.helper(first, second + nums[0], nums[1:], visited)


        visited[(first, second)] = result
        visited[(second, first)] = result
        return result
        
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