添加0059.螺旋矩阵II Swift 版本

Author: 余杜林

problems/0059.螺旋矩阵II.md

@@ -302,6 +302,61 @@ func generateMatrix(n int) [][]int {
 }
 ```
 
+Swift:
+
+```swift
+func generateMatrix(_ n: Int) -> [[Int]] {
+    var result = [[Int]](repeating: [Int](repeating: 0, count: n), count: n)
+
+    var startRow = 0
+    var startColumn = 0
+    var loopCount = n / 2
+    let mid = n / 2
+    var count = 1
+    var offset = 1
+    var row: Int
+    var column: Int
+
+    while loopCount > 0 {
+        row = startRow
+        column = startColumn
+
+        for c in column ..< startColumn + n - offset {
+            result[startRow][c] = count
+            count += 1
+            column += 1
+        }
+
+        for r in row ..< startRow + n - offset {
+            result[r][column] = count
+            count += 1
+            row += 1
+        }
+
+        for _ in startColumn ..< column {
+            result[row][column] = count
+            count += 1
+            column -= 1
+        }
+
+        for _ in startRow ..< row {
+            result[row][column] = count
+            count += 1
+            row -= 1
+        }
+
+        startRow += 1
+        startColumn += 1
+        offset += 2
+        loopCount -= 1
+    }
+
+    if (n % 2) != 0 {
+        result[mid][mid] = count
+    }
+    return result
+}
+```