feat: add swift implementation to lcof problem: No.04 (doocs#2830)

Author: klever34

lcof/面试题04. 二维数组中的查找/README.md

@@ -224,6 +224,21 @@ public class Solution {
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    func findNumberIn2DArray(_ matrix: [[Int]], _ target: Int) -> Bool {
+        for row in matrix {
+            if let _ = row.firstIndex(of: target) {
+                return true
+            }
+        }
+        return false
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof/面试题04. 二维数组中的查找/Solution.swift

@@ -0,0 +1,10 @@
+class Solution {
+    func findNumberIn2DArray(_ matrix: [[Int]], _ target: Int) -> Bool {
+        for row in matrix {
+            if let _ = row.firstIndex(of: target) {
+                return true
+            }
+        }
+        return false
+    }
+}