feat: add swift implementation to lcof problem: No.29 (doocs#2896)

Author: klever34

lcof/面试题29. 顺时针打印矩阵/README.md

@@ -326,6 +326,40 @@ public class Solution {
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    func spiralOrder(_ matrix: [[Int]]) -> [Int] {
+        guard !matrix.isEmpty && !matrix[0].isEmpty else {
+            return []
+        }
+        
+        let m = matrix.count
+        let n = matrix[0].count
+        var vis = Array(repeating: Array(repeating: false, count: n), count: m)
+        var ans = [Int]()
+        var i = 0, j = 0, k = 0
+        let dirs = [0, 1, 0, -1, 0]
+        
+        for _ in 0..<m*n {
+            ans.append(matrix[i][j])
+            vis[i][j] = true
+            var x = i + dirs[k], y = j + dirs[k + 1]
+            if x < 0 || y < 0 || x >= m || y >= n || vis[x][y] {
+                k = (k + 1) % 4
+                x = i + dirs[k]
+                y = j + dirs[k + 1]
+            }
+            i = x
+            j = y
+        }
+        
+        return ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof/面试题29. 顺时针打印矩阵/Solution.swift

@@ -0,0 +1,29 @@
+class Solution {
+    func spiralOrder(_ matrix: [[Int]]) -> [Int] {
+        guard !matrix.isEmpty && !matrix[0].isEmpty else {
+            return []
+        }
+        
+        let m = matrix.count
+        let n = matrix[0].count
+        var vis = Array(repeating: Array(repeating: false, count: n), count: m)
+        var ans = [Int]()
+        var i = 0, j = 0, k = 0
+        let dirs = [0, 1, 0, -1, 0]
+        
+        for _ in 0..<m*n {
+            ans.append(matrix[i][j])
+            vis[i][j] = true
+            var x = i + dirs[k], y = j + dirs[k + 1]
+            if x < 0 || y < 0 || x >= m || y >= n || vis[x][y] {
+                k = (k + 1) % 4
+                x = i + dirs[k]
+                y = j + dirs[k + 1]
+            }
+            i = x
+            j = y
+        }
+        
+        return ans
+    }
+}