<p>You are given an integer array <code>nums</code> and an integer <code>k</code>. Find the maximum subarray sum of all the subarrays of <code>nums</code> that meet the following conditions:</p>

<ul>
	<li>The length of the subarray is <code>k</code>, and</li>
	<li>All the elements of the subarray are <strong>distinct</strong>.</li>
</ul>

<p>Return <em>the maximum subarray sum of all the subarrays that meet the conditions</em><em>.</em> If no subarray meets the conditions, return <code>0</code>.</p>

<p><em>A <strong>subarray</strong> is a contiguous non-empty sequence of elements within an array.</em></p>

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

<pre>
<strong>Input:</strong> nums = [1,5,4,2,9,9,9], k = 3
<strong>Output:</strong> 15
<strong>Explanation:</strong> The subarrays of nums with length 3 are:
- [1,5,4] which meets the requirements and has a sum of 10.
- [5,4,2] which meets the requirements and has a sum of 11.
- [4,2,9] which meets the requirements and has a sum of 15.
- [2,9,9] which does not meet the requirements because the element 9 is repeated.
- [9,9,9] which does not meet the requirements because the element 9 is repeated.
We return 15 because it is the maximum subarray sum of all the subarrays that meet the conditions
</pre>

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

<pre>
<strong>Input:</strong> nums = [4,4,4], k = 3
<strong>Output:</strong> 0
<strong>Explanation:</strong> The subarrays of nums with length 3 are:
- [4,4,4] which does not meet the requirements because the element 4 is repeated.
We return 0 because no subarrays meet the conditions.
</pre>

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

<ul>
	<li><code>1 &lt;= k &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
</ul>

class Solution:
    def maximumSubarraySum(self, nums: List[int], k: int) -> int:
        sm, c = sum(nums[:k]), Counter(nums[:k])
        multiples = set(n for n in c if c[n]>1)
        ans = sm if not multiples else 0

        for old, new in zip(nums, nums[k:]):
            if old == new:
                continue
            c[old]-=1
            c[new]+=1
            sm+=new-old

            if c[old] == 1:
                multiples.remove(old)
            if c[new] > 1:
                multiples.add(new)
            if not multiples:
                ans = max(ans, sm)
        return ans

# time complexity: O(n)
# space complexity: O(1)

        
578