螺旋矩阵

/**
 * 
 * @param matrix int整型二维数组 
 * @return int整型一维数组
 */
function spiralOrder( matrix ) {
    // write code here
    if(matrix.length === 0){
        return []
    }
    let left = 0
    let right = matrix[0].length-1
    let top = 0
    let bottom = matrix.length-1
    let res = []
    let direction = "right"
    while(left<=right && top <= bottom){
        if(direction === "right"){
            for(let i = left;i<= right ;i++){
               res.push(matrix[top][i])     
            }
            top++
            direction = "down"
        }else if(direction === "down"){
           for(let i = top;i<=bottom;i++){
               res.push(matrix[i][right])
           }
            right--
            direction = 'left'
        }else if(direction === "left"){
            for(let i = right;i>=left;i--){
                res.push(matrix[bottom][i])
            }
            bottom--
            direction = "top"
        }else if(direction === "top"){
            for(let i = bottom;i>=top;i--){
                res.push(matrix[i][left])
            }
            left++
            direction = "right"
        }
    }
    return res
    }
module.exports = {
    spiralOrder : spiralOrder
};