feat: add swift implementation to lcp problem: No.63 (#3973)

Author: klever34

lcp/LCP 63. 弹珠游戏/README.md

@@ -274,6 +274,80 @@ func ballGame(num int, plate []string) (ans [][]int) {
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    private var plate: [String] = []
+    private var num: Int = 0
+    private var m: Int = 0
+    private var n: Int = 0
+    private let dirs = [0, 1, 0, -1, 0]
+
+    func ballGame(_ num: Int, _ plate: [String]) -> [[Int]] {
+        self.num = num
+        self.plate = plate
+        self.m = plate.count
+        self.n = plate[0].count
+        var ans: [[Int]] = []
+
+        for i in 1..<m - 1 {
+            if plate[i][0] == "." && check(i, 0, 0) {
+                ans.append([i, 0])
+            }
+            if plate[i][n - 1] == "." && check(i, n - 1, 2) {
+                ans.append([i, n - 1])
+            }
+        }
+
+        for j in 1..<n - 1 {
+            if plate[0][j] == "." && check(0, j, 1) {
+                ans.append([0, j])
+            }
+            if plate[m - 1][j] == "." && check(m - 1, j, 3) {
+                ans.append([m - 1, j])
+            }
+        }
+
+        return ans
+    }
+
+    private func check(_ i: Int, _ j: Int, _ d: Int) -> Bool {
+        var k = num
+        var i = i, j = j, d = d
+
+        while plate[i][j] != "O" {
+            if k == 0 {
+                return false
+            }
+
+            if plate[i][j] == "W" {
+                d = (d + 3) % 4
+            } else if plate[i][j] == "E" {
+                d = (d + 1) % 4
+            }
+
+            i += dirs[d]
+            j += dirs[d + 1]
+
+            if i < 0 || i >= m || j < 0 || j >= n {
+                return false
+            }
+
+            k -= 1
+        }
+
+        return true
+    }
+}
+
+private extension String {
+    subscript(_ index: Int) -> Character {
+        return self[self.index(self.startIndex, offsetBy: index)]
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcp/LCP 63. 弹珠游戏/Solution.swift

@@ -0,0 +1,69 @@
+class Solution {
+    private var plate: [String] = []
+    private var num: Int = 0
+    private var m: Int = 0
+    private var n: Int = 0
+    private let dirs = [0, 1, 0, -1, 0]
+
+    func ballGame(_ num: Int, _ plate: [String]) -> [[Int]] {
+        self.num = num
+        self.plate = plate
+        self.m = plate.count
+        self.n = plate[0].count
+        var ans: [[Int]] = []
+
+        for i in 1..<m - 1 {
+            if plate[i][0] == "." && check(i, 0, 0) {
+                ans.append([i, 0])
+            }
+            if plate[i][n - 1] == "." && check(i, n - 1, 2) {
+                ans.append([i, n - 1])
+            }
+        }
+
+        for j in 1..<n - 1 {
+            if plate[0][j] == "." && check(0, j, 1) {
+                ans.append([0, j])
+            }
+            if plate[m - 1][j] == "." && check(m - 1, j, 3) {
+                ans.append([m - 1, j])
+            }
+        }
+
+        return ans
+    }
+
+    private func check(_ i: Int, _ j: Int, _ d: Int) -> Bool {
+        var k = num
+        var i = i, j = j, d = d
+
+        while plate[i][j] != "O" {
+            if k == 0 {
+                return false
+            }
+
+            if plate[i][j] == "W" {
+                d = (d + 3) % 4
+            } else if plate[i][j] == "E" {
+                d = (d + 1) % 4
+            }
+
+            i += dirs[d]
+            j += dirs[d + 1]
+
+            if i < 0 || i >= m || j < 0 || j >= n {
+                return false
+            }
+
+            k -= 1
+        }
+
+        return true
+    }
+}
+
+private extension String {
+    subscript(_ index: Int) -> Character {
+        return self[self.index(self.startIndex, offsetBy: index)]
+    }
+}