54. 螺旋矩阵

自己想的= =。。 因为swift的区间问题吧= =。。每次进行下一步都做了下判断。。感觉挺扯的

func spiralOrder(_ matrix: [[Int]]) -> [Int] {

        var ans = [Int]()
        let row = matrix.count
        let col = matrix.first?.count ?? 0
        var left = 0, right = col ,top = 0 ,bottom = row
        
        while true {
            
           if left >= right {
               break
           }
            //从左到右
            for i in left..<right {
                ans.append(matrix[top][i])
            }
            // print(ans)
            right -= 1
            top += 1
            if top >= bottom {
                break
            }
            //从上到下
            for i in top..<bottom {
                ans.append(matrix[i][right])
            }
            bottom -= 1
            // print(ans)
            
            if left >= right {
                break
            }
            //从右到左
            for i in (left..<right).reversed() {
                ans.append(matrix[bottom][i])
            }
            // print(ans)
           
           if top >= bottom {
               break
           }
            //从下往上
            for i in (top..<bottom).reversed() {
                ans.append(matrix[i][left])
            }
            // print(ans)
            left += 1
               
        }
        return ans
    
    }

优化版本

func spiralOrder(_ matrix: [[Int]]) -> [Int] {

        var ans = [Int]()
        var left = 0, right = matrix.first?.count ?? 0 ,top = 0 ,bottom = matrix.count
        
        while true {

            //从左到右
            for i in left..<right {
                ans.append(matrix[top][i])
            }
            // print(ans)
            right -= 1
            top += 1
            if top >= bottom {
                break
            }
            //从上到下
            for i in top..<bottom {
                ans.append(matrix[i][right])
            }
            bottom -= 1
            // print(ans)
            
            if left >= right {
                break
            }
            //从右到左
            for i in (left..<right).reversed() {
                ans.append(matrix[bottom][i])
            }
            // print(ans)
           
           if top >= bottom {
               break
           }
            //从下往上
            for i in (top..<bottom).reversed() {
                ans.append(matrix[i][left])
            }
            // print(ans)
            left += 1
             if left >= right {
               break
           }
               
        }
        return ans
    
    }