Add Longest Substring With Unique Chars

Author: marttp

kotlin/Sliding Windows/LongestSubstringWithUniqueChars.kt

@@ -0,0 +1,21 @@
+fun longestSubstringWithUniqueChars(s: String): Int {
+    var maxLen = 0
+    val hashSet = mutableSetOf<Char>()
+    var left = 0
+    var right = 0
+    while (right < s.length) {
+        // If we encounter a duplicate character in the window, shrink
+        // the window until it's no longer a duplicate.
+        while (s[right] in hashSet) {
+            hashSet.remove(s[left])
+            left++
+        }
+        // Once there are no more duplicates in the window, update
+        // 'maxLen' if the current window is larger.
+        maxLen = maxOf(maxLen, right - left + 1)
+        hashSet.add(s[right])
+        // Expand the window.
+        right++
+    }
+    return maxLen
+}