Merge pull request #2128 from AyselHeydarova/Leetcode-0424

Create: 0424-longest-repeating-character-replacement.swift

swift/0424-longest-repeating-character-replacement.swift

@@ -0,0 +1,21 @@
+class Solution {
+    func characterReplacement(_ s: String, _ k: Int) -> Int {
+        var count: [Character: Int] = [:]
+        var strArray = Array(s)
+        var result = 0
+        var l = 0
+        var maxF = 0
+
+        for r in 0...s.count - 1 {
+            count[strArray[r]] = count[strArray[r], default: 0] + 1
+            maxF = max(maxF, count[strArray[r], default: 0])
+
+            while (r - l + 1) - maxF > k {
+                count[strArray[l]] = count[strArray[l], default: 0] - 1
+                l += 1 
+            }
+            result = max(result, r - l + 1)
+        }
+        return result
+    }
+}