添加 242.有效的字母异位词 Swift版本

problems/0242.有效的字母异位词.md

@@ -198,6 +198,29 @@ var isAnagram = function(s, t) {
 };
 ```
 
+Swift：
+```Swift
+func isAnagram(_ s: String, _ t: String) -> Bool {
+    if s.count != t.count {
+        return false
+    }
+    var record = Array(repeating: 0, count: 26)
+    let aUnicodeScalar = "a".unicodeScalars.first!.value
+    for c in s.unicodeScalars {
+        record[Int(c.value - aUnicodeScalar)] += 1
+    }
+    for c in t.unicodeScalars {
+        record[Int(c.value - aUnicodeScalar)] -= 1
+    }
+    for value in record {
+        if value != 0 {
+            return false
+        }
+    }
+    return true
+}
+```
+
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