feat: add swift implementation to lcp problem: No.56 (#3931)

doocs · Jan 6, 2025 · 2dd558c · 2dd558c
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diff --git a/lcp/LCP 56. 信物传送/README.md b/lcp/LCP 56. 信物传送/README.md
@@ -271,6 +271,57 @@ function conveyorBelt(matrix: string[], start: number[], end: number[]): number
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    func conveyorBelt(_ matrix: [String], _ start: [Int], _ end: [Int]) -> Int {
+        let directions: [(Int, Int)] = [(-1, 0), (0, 1), (1, 0), (0, -1)]
+        let directionMap: [Character: Int] = ["^": 0, ">": 1, "v": 2, "<": 3]
+
+        let rows = matrix.count
+        let cols = matrix[0].count
+
+        var dist = Array(repeating: Array(repeating: Int.max, count: cols), count: rows)
+        var deque: [(Int, Int)] = []
+
+        dist[start[0]][start[1]] = 0
+        deque.append((start[0], start[1]))
+
+        while !deque.isEmpty {
+            let (i, j) = deque.removeFirst()
+
+            if i == end[0] && j == end[1] {
+                return dist[i][j]
+            }
+
+            for (k, (di, dj)) in directions.enumerated() {
+                let ni = i + di
+                let nj = j + dj
+
+                if ni >= 0 && ni < rows && nj >= 0 && nj < cols {
+                    let currentChar = matrix[i][matrix[i].index(matrix[i].startIndex, offsetBy: j)]
+                    let additionalCost = directionMap[currentChar] == k ? 0 : 1
+                    let newDist = dist[i][j] + additionalCost
+
+                    if newDist < dist[ni][nj] {
+                        dist[ni][nj] = newDist
+
+                        if additionalCost == 0 {
+                            deque.insert((ni, nj), at: 0)
+                        } else {
+                            deque.append((ni, nj))
+                        }
+                    }
+                }
+            }
+        }
+
+        return -1
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

diff --git a/lcp/LCP 56. 信物传送/Solution.swift b/lcp/LCP 56. 信物传送/Solution.swift
@@ -0,0 +1,46 @@
+class Solution {
+    func conveyorBelt(_ matrix: [String], _ start: [Int], _ end: [Int]) -> Int {
+        let directions: [(Int, Int)] = [(-1, 0), (0, 1), (1, 0), (0, -1)]
+        let directionMap: [Character: Int] = ["^": 0, ">": 1, "v": 2, "<": 3]
+
+        let rows = matrix.count
+        let cols = matrix[0].count
+
+        var dist = Array(repeating: Array(repeating: Int.max, count: cols), count: rows)
+        var deque: [(Int, Int)] = []
+
+        dist[start[0]][start[1]] = 0
+        deque.append((start[0], start[1]))
+
+        while !deque.isEmpty {
+            let (i, j) = deque.removeFirst()
+
+            if i == end[0] && j == end[1] {
+                return dist[i][j]
+            }
+
+            for (k, (di, dj)) in directions.enumerated() {
+                let ni = i + di
+                let nj = j + dj
+
+                if ni >= 0 && ni < rows && nj >= 0 && nj < cols {
+                    let currentChar = matrix[i][matrix[i].index(matrix[i].startIndex, offsetBy: j)]
+                    let additionalCost = directionMap[currentChar] == k ? 0 : 1
+                    let newDist = dist[i][j] + additionalCost
+
+                    if newDist < dist[ni][nj] {
+                        dist[ni][nj] = newDist
+
+                        if additionalCost == 0 {
+                            deque.insert((ni, nj), at: 0)
+                        } else {
+                            deque.append((ni, nj))
+                        }
+                    }
+                }
+            }
+        }
+
+        return -1
+    }
+}