solve

Author: sonjh1217

longest-substring-without-repeating-characters/sonjh1217.swift

@@ -0,0 +1,19 @@
+class Solution {
+    // O(n) time / O(n) space
+    func lengthOfLongestSubstring(_ s: String) -> Int {
+        var lastIndexByCharacter = [Character: Int]()
+        var start = 0
+        var maxLenth = 0
+
+        for (i, character) in s.enumerated() {
+            if let lastIndex = lastIndexByCharacter[character],
+                lastIndex >= start {
+                start = lastIndex + 1
+            }
+            lastIndexByCharacter[character] = i
+            maxLenth = max(maxLenth, i - start + 1)
+        }
+        return maxLenth
+    }
+}
+