51螺旋矩阵.md

和59一样，但每次更新count后要check是否达到目标数了，达到则返回：

func spiralOrder(matrix [][]int) []int {
    m, n := len(matrix), len(matrix[0])
    res := make([]int, m * n)
    top, bottom := 0, m - 1
    left, right := 0, n - 1
    count := 0
    for count < m * n {
        // left-right
        for x := left; x <= right; x++ {
            res[count] = matrix[top][x]
            count++
            if count >= m * n { return res }
        }
        top++
        // top-bottom
        for y := top; y <= bottom; y++ {
            res[count] = matrix[y][right]
            count++
            if count >= m * n { return res }
        }
        right--
        // right-left
        for x := right; x >= left; x-- {
            res[count] = matrix[bottom][x]
            count++
            if count >= m * n { return res }
        }
        bottom--
        // bottom-top
        for y := bottom; y >= top; y-- {
            res[count] = matrix[y][left]
            count++
            if count >= m * n { return res }
        }
        left++
    }
    return res
}