kt: add «763. Partition Labels»

URL:	https://leetcode.com/problems/partition-labels/
Signed-off-by: Matej Focko <me@mfocko.xyz>

kt/partition-labels.kt

@@ -0,0 +1,32 @@
+class Solution {
+    fun partitionLabels(s: String): List<Int> {
+        val (firstIndex, lastIndex) = IntArray(26) to IntArray(26)
+        s.withIndex().forEach { (index, c) ->
+            lastIndex[c - 'a'] = index
+        }
+
+        val sizes = mutableListOf<Int>()
+
+        var (start, end) = 0 to 0
+        s.withIndex().forEach { (i, c) ->
+            val idx = c - 'a'
+            if (firstIndex[idx] == 0) {
+                firstIndex[idx] = i
+            }
+
+            if (end < firstIndex[idx]) {
+                sizes.add(end - start + 1)
+                start = i
+                end = i
+            }
+
+            end = maxOf(end, lastIndex[idx])
+        }
+
+        if (end - start + 1 > 0) {
+            sizes.add(end - start + 1)
+        }
+
+        return sizes
+    }
+}