feat: add swift implementation to lcci problem: No.08.14 (doocs#2706)

Author: klever34

lcci/08.14.Boolean Evaluation/README.md

@@ -190,6 +190,57 @@ func countEval(s string, result int) int {
 }
 ```
 
+```swift
+class Solution {
+    private var memo = [String: [Int]]()
+
+    func countEval(_ s: String, _ result: Int) -> Int {
+        memo = [:]
+        let ans = dfs(s)
+        return result == 0 || result == 1 ? ans[result] : 0
+    }
+
+    private func dfs(_ s: String) -> [Int] {
+        if let res = memo[s] {
+            return res
+        }
+
+        var res = [0, 0]
+        if s.count == 1 {
+            res[Int(String(s))!] = 1
+            return res
+        }
+
+        for k in 0..<s.count {
+            let index = s.index(s.startIndex, offsetBy: k)
+            let op = String(s[index])
+
+            if op == "&" || op == "|" || op == "^" {
+                let left = dfs(String(s[s.startIndex..<index]))
+                let right = dfs(String(s[s.index(after: index)...]))
+
+                for i in 0...1 {
+                    for j in 0...1 {
+                        var v = 0
+                        if op == "&" {
+                            v = i & j
+                        } else if op == "|" {
+                            v = i | j
+                        } else if op == "^" {
+                            v = i ^ j
+                        }
+                        res[v] += left[i] * right[j]
+                    }
+                }
+            }
+        }
+
+        memo[s] = res
+        return res
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/08.14.Boolean Evaluation/README_EN.md

@@ -201,6 +201,57 @@ func countEval(s string, result int) int {
 }
 ```
 
+```swift
+class Solution {
+    private var memo = [String: [Int]]()
+
+    func countEval(_ s: String, _ result: Int) -> Int {
+        memo = [:]
+        let ans = dfs(s)
+        return result == 0 || result == 1 ? ans[result] : 0
+    }
+
+    private func dfs(_ s: String) -> [Int] {
+        if let res = memo[s] {
+            return res
+        }
+
+        var res = [0, 0]
+        if s.count == 1 {
+            res[Int(String(s))!] = 1
+            return res
+        }
+
+        for k in 0..<s.count {
+            let index = s.index(s.startIndex, offsetBy: k)
+            let op = String(s[index])
+
+            if op == "&" || op == "|" || op == "^" {
+                let left = dfs(String(s[s.startIndex..<index]))
+                let right = dfs(String(s[s.index(after: index)...]))
+
+                for i in 0...1 {
+                    for j in 0...1 {
+                        var v = 0
+                        if op == "&" {
+                            v = i & j
+                        } else if op == "|" {
+                            v = i | j
+                        } else if op == "^" {
+                            v = i ^ j
+                        }
+                        res[v] += left[i] * right[j]
+                    }
+                }
+            }
+        }
+
+        memo[s] = res
+        return res
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/08.14.Boolean Evaluation/Solution.swift

@@ -0,0 +1,48 @@
+class Solution {
+    private var memo = [String: [Int]]()
+
+    func countEval(_ s: String, _ result: Int) -> Int {
+        memo = [:]
+        let ans = dfs(s)
+        return result == 0 || result == 1 ? ans[result] : 0
+    }
+
+    private func dfs(_ s: String) -> [Int] {
+        if let res = memo[s] {
+            return res
+        }
+        
+        var res = [0, 0]
+        if s.count == 1 {
+            res[Int(String(s))!] = 1
+            return res
+        }
+
+        for k in 0..<s.count {
+            let index = s.index(s.startIndex, offsetBy: k)
+            let op = String(s[index])
+
+            if op == "&" || op == "|" || op == "^" {
+                let left = dfs(String(s[s.startIndex..<index]))
+                let right = dfs(String(s[s.index(after: index)...]))
+                
+                for i in 0...1 {
+                    for j in 0...1 {
+                        var v = 0
+                        if op == "&" {
+                            v = i & j
+                        } else if op == "|" {
+                            v = i | j
+                        } else if op == "^" {
+                            v = i ^ j
+                        }
+                        res[v] += left[i] * right[j]
+                    }
+                }
+            }
+        }
+
+        memo[s] = res
+        return res
+    }
+}