kt: add «2461. Maximum Sum of Distinct Subarrays With Length K»

URL:	https://leetcode.com/problems/maximum-sum-of-distinct-subarrays-with-length-k/
Signed-off-by: Matej Focko <me@mfocko.xyz>

kt/maximum-sum-of-distinct-subarrays-with-length-k.kt

@@ -0,0 +1,33 @@
+class Solution {
+    fun maximumSubarraySum(
+        nums: IntArray,
+        k: Int,
+    ): Long {
+        var maximum = 0L
+
+        var (l, r) = 0 to 0
+        var runningSum = 0
+
+        val seen = mutableMapOf<Int, Int>()
+        while (r < nums.size) {
+            val x = nums[r]
+
+            val lastSeen = seen.getOrElse(x) { -1 }
+            while (l <= lastSeen || r - l + 1 > k) {
+                runningSum -= nums[l]
+                l += 1
+            }
+
+            seen.put(x, r)
+            runningSum += nums[r]
+
+            if (end - begin + 1 == k) {
+                maximum = listOf(maximum, runningSum).max()
+            }
+
+            r += 1
+        }
+
+        return maximum
+    }
+}