feat: add swift implementation to lcof2 problem: No.112 (#3690)

Author: klever34

lcof2/剑指 Offer II 112. 最长递增路径/README.md

@@ -205,6 +205,49 @@ func longestIncreasingPath(matrix [][]int) int {
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    private var memo: [[Int]] = []
+    private var matrix: [[Int]] = []
+    private var m: Int = 0
+    private var n: Int = 0
+
+    func longestIncreasingPath(_ matrix: [[Int]]) -> Int {
+        self.matrix = matrix
+        m = matrix.count
+        n = matrix[0].count
+        memo = Array(repeating: Array(repeating: -1, count: n), count: m)
+        
+        var ans = 0
+        for i in 0..<m {
+            for j in 0..<n {
+                ans = max(ans, dfs(i, j))
+            }
+        }
+        return ans
+    }
+
+    private func dfs(_ i: Int, _ j: Int) -> Int {
+        if memo[i][j] != -1 {
+            return memo[i][j]
+        }
+        var ans = 1
+        let dirs = [(-1, 0), (1, 0), (0, -1), (0, 1)]
+        
+        for (dx, dy) in dirs {
+            let x = i + dx, y = j + dy
+            if x >= 0, x < m, y >= 0, y < n, matrix[x][y] > matrix[i][j] {
+                ans = max(ans, dfs(x, y) + 1)
+            }
+        }
+        memo[i][j] = ans
+        return ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 112. 最长递增路径/Solution.swift

@@ -0,0 +1,38 @@
+class Solution {
+    private var memo: [[Int]] = []
+    private var matrix: [[Int]] = []
+    private var m: Int = 0
+    private var n: Int = 0
+
+    func longestIncreasingPath(_ matrix: [[Int]]) -> Int {
+        self.matrix = matrix
+        m = matrix.count
+        n = matrix[0].count
+        memo = Array(repeating: Array(repeating: -1, count: n), count: m)
+        
+        var ans = 0
+        for i in 0..<m {
+            for j in 0..<n {
+                ans = max(ans, dfs(i, j))
+            }
+        }
+        return ans
+    }
+
+    private func dfs(_ i: Int, _ j: Int) -> Int {
+        if memo[i][j] != -1 {
+            return memo[i][j]
+        }
+        var ans = 1
+        let dirs = [(-1, 0), (1, 0), (0, -1), (0, 1)]
+        
+        for (dx, dy) in dirs {
+            let x = i + dx, y = j + dy
+            if x >= 0, x < m, y >= 0, y < n, matrix[x][y] > matrix[i][j] {
+                ans = max(ans, dfs(x, y) + 1)
+            }
+        }
+        memo[i][j] = ans
+        return ans
+    }
+}