feat: add swift implementation to lcp problem: No.03 (#3720)

Author: klever34

lcp/LCP 03. 机器人大冒险/README.md

@@ -239,6 +239,49 @@ function robot(command: string, obstacles: number[][], x: number, y: number): bo
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    func robot(_ command: String, _ obstacles: [[Int]], _ x: Int, _ y: Int) -> Bool {
+        var visited: Set<[Int]> = []
+        var i = 0, j = 0
+        visited.insert([i, j])
+        
+        for c in command {
+            if c == "U" {
+                j += 1
+            } else {
+                i += 1
+            }
+            visited.insert([i, j])
+        }
+        
+        func canReach(_ targetX: Int, _ targetY: Int) -> Bool {
+            let k = min(targetX / i, targetY / j)
+            return visited.contains([targetX - k * i, targetY - k * j])
+        }
+        
+        if !canReach(x, y) {
+            return false
+        }
+        
+        for obstacle in obstacles {
+            let obstacleX = obstacle[0]
+            let obstacleY = obstacle[1]
+            if obstacleX > x || obstacleY > y {
+                continue
+            }
+            if canReach(obstacleX, obstacleY) {
+                return false
+            }
+        }
+        
+        return true
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcp/LCP 03. 机器人大冒险/Solution.swift

@@ -0,0 +1,38 @@
+class Solution {
+    func robot(_ command: String, _ obstacles: [[Int]], _ x: Int, _ y: Int) -> Bool {
+        var visited: Set<[Int]> = []
+        var i = 0, j = 0
+        visited.insert([i, j])
+        
+        for c in command {
+            if c == "U" {
+                j += 1
+            } else {
+                i += 1
+            }
+            visited.insert([i, j])
+        }
+        
+        func canReach(_ targetX: Int, _ targetY: Int) -> Bool {
+            let k = min(targetX / i, targetY / j)
+            return visited.contains([targetX - k * i, targetY - k * j])
+        }
+        
+        if !canReach(x, y) {
+            return false
+        }
+        
+        for obstacle in obstacles {
+            let obstacleX = obstacle[0]
+            let obstacleY = obstacle[1]
+            if obstacleX > x || obstacleY > y {
+                continue
+            }
+            if canReach(obstacleX, obstacleY) {
+                return false
+            }
+        }
+        
+        return true
+    }
+}