feat: add swift implementation to lcci problem: No.17.17 (doocs#2804)

lcci/17.17.Multi Search/README.md

@@ -246,6 +246,76 @@ func multiSearch(big string, smalls []string) [][]int {
 }
 ```
 
+```swift
+class TrieNode {
+    var idx: Int
+    var children: [TrieNode?]
+
+    init() {
+        self.idx = -1
+        self.children = Array(repeating: nil, count: 26)
+    }
+}
+
+class Trie {
+    private let root: TrieNode
+
+    init() {
+        self.root = TrieNode()
+    }
+
+    func insert(_ word: String, _ index: Int) {
+        var node = root
+        for ch in word {
+            let i = Int(ch.asciiValue! - Character("a").asciiValue!)
+            if node.children[i] == nil {
+                node.children[i] = TrieNode()
+            }
+            node = node.children[i]!
+        }
+        node.idx = index
+    }
+
+    func search(_ word: String) -> [Int] {
+        var node = root
+        var results = [Int]()
+        for ch in word {
+            let i = Int(ch.asciiValue! - Character("a").asciiValue!)
+            if node.children[i] == nil {
+                break
+            }
+            node = node.children[i]!
+            if node.idx != -1 {
+                results.append(node.idx)
+            }
+        }
+        return results
+    }
+}
+
+class Solution {
+    func multiSearch(_ big: String, _ smalls: [String]) -> [[Int]] {
+        let trie = Trie()
+        for (index, small) in smalls.enumerated() {
+            trie.insert(small, index)
+        }
+
+        var results = Array(repeating: [Int](), count: smalls.count)
+        let bigChars = Array(big)
+
+        for i in 0..<bigChars.count {
+            let substring = String(bigChars[i...])
+            let indices = trie.search(substring)
+            for index in indices {
+                results[index].append(i)
+            }
+        }
+
+        return results
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/17.17.Multi Search/README_EN.md

@@ -251,6 +251,76 @@ func multiSearch(big string, smalls []string) [][]int {
 }
 ```
 
+```swift
+class TrieNode {
+    var idx: Int
+    var children: [TrieNode?]
+
+    init() {
+        self.idx = -1
+        self.children = Array(repeating: nil, count: 26)
+    }
+}
+
+class Trie {
+    private let root: TrieNode
+
+    init() {
+        self.root = TrieNode()
+    }
+
+    func insert(_ word: String, _ index: Int) {
+        var node = root
+        for ch in word {
+            let i = Int(ch.asciiValue! - Character("a").asciiValue!)
+            if node.children[i] == nil {
+                node.children[i] = TrieNode()
+            }
+            node = node.children[i]!
+        }
+        node.idx = index
+    }
+
+    func search(_ word: String) -> [Int] {
+        var node = root
+        var results = [Int]()
+        for ch in word {
+            let i = Int(ch.asciiValue! - Character("a").asciiValue!)
+            if node.children[i] == nil {
+                break
+            }
+            node = node.children[i]!
+            if node.idx != -1 {
+                results.append(node.idx)
+            }
+        }
+        return results
+    }
+}
+
+class Solution {
+    func multiSearch(_ big: String, _ smalls: [String]) -> [[Int]] {
+        let trie = Trie()
+        for (index, small) in smalls.enumerated() {
+            trie.insert(small, index)
+        }
+
+        var results = Array(repeating: [Int](), count: smalls.count)
+        let bigChars = Array(big)
+
+        for i in 0..<bigChars.count {
+            let substring = String(bigChars[i...])
+            let indices = trie.search(substring)
+            for index in indices {
+                results[index].append(i)
+            }
+        }
+
+        return results
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/17.17.Multi Search/Solution.swift

@@ -0,0 +1,67 @@
+class TrieNode {
+    var idx: Int
+    var children: [TrieNode?]
+
+    init() {
+        self.idx = -1
+        self.children = Array(repeating: nil, count: 26)
+    }
+}
+
+class Trie {
+    private let root: TrieNode
+
+    init() {
+        self.root = TrieNode()
+    }
+
+    func insert(_ word: String, _ index: Int) {
+        var node = root
+        for ch in word {
+            let i = Int(ch.asciiValue! - Character("a").asciiValue!)
+            if node.children[i] == nil {
+                node.children[i] = TrieNode()
+            }
+            node = node.children[i]!
+        }
+        node.idx = index
+    }
+
+    func search(_ word: String) -> [Int] {
+        var node = root
+        var results = [Int]()
+        for ch in word {
+            let i = Int(ch.asciiValue! - Character("a").asciiValue!)
+            if node.children[i] == nil {
+                break
+            }
+            node = node.children[i]!
+            if node.idx != -1 {
+                results.append(node.idx)
+            }
+        }
+        return results
+    }
+}
+
+class Solution {
+    func multiSearch(_ big: String, _ smalls: [String]) -> [[Int]] {
+        let trie = Trie()
+        for (index, small) in smalls.enumerated() {
+            trie.insert(small, index)
+        }
+
+        var results = Array(repeating: [Int](), count: smalls.count)
+        let bigChars = Array(big)
+
+        for i in 0..<bigChars.count {
+            let substring = String(bigChars[i...])
+            let indices = trie.search(substring)
+            for index in indices {
+                results[index].append(i)
+            }
+        }
+
+        return results
+    }
+}