<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:
        def canPart(lsum, rsum, nums, i, seen):
            key = (lsum, rsum)
            if key in seen or (rsum, lsum) in seen:
                return 
            if i == len(nums):
                seen[key] = lsum == rsum
            else:
                seen[key] = canPart(lsum+nums[i], rsum, nums, i+1, seen) or canPart(lsum, rsum+nums[i], nums, i+1, seen)
            return seen[key]
        seen = {}
        return canPart(nums[0], 0, nums, 1, seen)
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