feat: add swift implementation to lcci problem: No.16.15 (#2746)

Author: klever34

Diff for: lcci/16.15.Master Mind/README.md

@@ -122,6 +122,35 @@ var masterMind = function (solution, guess) {
 };
 ```
 
+```swift
+class Solution {
+    func masterMind(_ solution: String, _ guess: String) -> [Int] {
+        var x = 0
+        var y = 0
+        var cnt1: [Character: Int] = [:]
+        var cnt2: [Character: Int] = [:]
+        
+        for i in solution.indices {
+            let a = solution[i]
+            let b = guess[i]
+            if a == b {
+                x += 1
+            }
+            cnt1[a, default: 0] += 1
+            cnt2[b, default: 0] += 1
+        }
+        
+        let colors = "RYGB"
+        for c in colors {
+            let minCount = min(cnt1[c, default: 0], cnt2[c, default: 0])
+            y += minCount
+        }
+        
+        return [x, y - x]
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

Diff for: lcci/16.15.Master Mind/README_EN.md

@@ -129,6 +129,35 @@ var masterMind = function (solution, guess) {
 };
 ```
 
+```swift
+class Solution {
+    func masterMind(_ solution: String, _ guess: String) -> [Int] {
+        var x = 0
+        var y = 0
+        var cnt1: [Character: Int] = [:]
+        var cnt2: [Character: Int] = [:]
+        
+        for i in solution.indices {
+            let a = solution[i]
+            let b = guess[i]
+            if a == b {
+                x += 1
+            }
+            cnt1[a, default: 0] += 1
+            cnt2[b, default: 0] += 1
+        }
+        
+        let colors = "RYGB"
+        for c in colors {
+            let minCount = min(cnt1[c, default: 0], cnt2[c, default: 0])
+            y += minCount
+        }
+        
+        return [x, y - x]
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

Diff for: lcci/16.15.Master Mind/Solution.swift

@@ -0,0 +1,26 @@
+class Solution {
+    func masterMind(_ solution: String, _ guess: String) -> [Int] {
+        var x = 0
+        var y = 0
+        var cnt1: [Character: Int] = [:]
+        var cnt2: [Character: Int] = [:]
+        
+        for i in solution.indices {
+            let a = solution[i]
+            let b = guess[i]
+            if a == b {
+                x += 1
+            }
+            cnt1[a, default: 0] += 1
+            cnt2[b, default: 0] += 1
+        }
+        
+        let colors = "RYGB"
+        for c in colors {
+            let minCount = min(cnt1[c, default: 0], cnt2[c, default: 0])
+            y += minCount
+        }
+        
+        return [x, y - x]
+    }
+}