feat: add swift implementation to lcci problem: No.08.11 (doocs#2697)

Author: klever34

lcci/08.11.Coin/README.md

@@ -161,6 +161,27 @@ function waysToChange(n: number): number {
 }
 ```
 
+```swift
+class Solution {
+    func waysToChange(_ n: Int) -> Int {
+        let mod = Int(1e9 + 7)
+        let coins = [25, 10, 5, 1]
+        var f = Array(repeating: Array(repeating: 0, count: n + 1), count: 5)
+        f[0][0] = 1
+
+        for i in 1...4 {
+            for j in 0...n {
+                f[i][j] = f[i - 1][j]
+                if j >= coins[i - 1] {
+                    f[i][j] = (f[i][j] + f[i][j - coins[i - 1]]) % mod
+                }
+            }
+        }
+        return f[4][n]
+    }
+}
+```
+
 <!-- tabs:end -->
 
 ### 方法二：动态规划（空间优化）

lcci/08.11.Coin/README_EN.md

@@ -173,6 +173,27 @@ function waysToChange(n: number): number {
 }
 ```
 
+```swift
+class Solution {
+    func waysToChange(_ n: Int) -> Int {
+        let mod = Int(1e9 + 7)
+        let coins = [25, 10, 5, 1]
+        var f = Array(repeating: Array(repeating: 0, count: n + 1), count: 5)
+        f[0][0] = 1
+
+        for i in 1...4 {
+            for j in 0...n {
+                f[i][j] = f[i - 1][j]
+                if j >= coins[i - 1] {
+                    f[i][j] = (f[i][j] + f[i][j - coins[i - 1]]) % mod
+                }
+            }
+        }
+        return f[4][n]
+    }
+}
+```
+
 <!-- tabs:end -->
 
 ### Solution 2: Dynamic Programming (Space Optimization)

lcci/08.11.Coin/Solution.swift

@@ -0,0 +1,18 @@
+class Solution {
+    func waysToChange(_ n: Int) -> Int {
+        let mod = Int(1e9 + 7)
+        let coins = [25, 10, 5, 1]
+        var f = Array(repeating: Array(repeating: 0, count: n + 1), count: 5)
+        f[0][0] = 1
+
+        for i in 1...4 {
+            for j in 0...n {
+                f[i][j] = f[i - 1][j]
+                if j >= coins[i - 1] {
+                    f[i][j] = (f[i][j] + f[i][j - coins[i - 1]]) % mod
+                }
+            }
+        }
+        return f[4][n]
+    }
+}