一个数组的算法题，求最精简算法！

[kth007]

Array
(
    [0] => Array
        (
            [rowbegin] => a1
            [rowend] => a1
            [0] => Array
                (
                    [beginlab] => a1-1
                    [endlab] => a1-1
                    [color] => 
                    [text] => 第一条
                    [href] => 
                )
 
            [1] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 第二条
                    [href] => 
                )
 
        )
 
    [1] => Array
        (
            [rowbegin] => 
            [rowend] => 
            [0] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 
                    [href] => 
                )
 
            [1] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 
                    [href] => 
                )
 
        )
 
    [2] => Array
        (
            [rowbegin] => 
            [rowend] => 
            [0] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 
                    [href] => 
                )
 
            [1] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 不要上面的
                    [href] => 
                )
             [2] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 
                    [href] => 
                )
        )
 
    [3] => Array
        (
            [rowbegin] => 
            [rowend] => 
            [0] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 
                    [href] => 
                )
 
        )
 
    [4] => Array
        (
            [rowbegin] => 
            [rowend] => 
            [0] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 最后一条
                    [href] => 
                )
 
            [1] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 
                    [href] => 
                )
 
        )
 
)

有一数组 我希望通过最精简的算法 实现如下的结果

Array
(
    [0] => Array
        (
            [rowbegin] => a1
            [rowend] => a1
            [0] => Array
                (
                    [beginlab] => a1-1
                    [endlab] => a1-1
                    [color] => 
                    [text] => 第一条
                    [href] => 
                )
 
            [1] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 第二条
                    [href] => 
                )
 
        )
 
    [1] => Array
        (
            [rowbegin] => 
            [rowend] => 
            [0] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 
                    [href] => 
                )
        )
 
    [2] => Array
        (
            [rowbegin] => 
            [rowend] => 
            [0] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 不要上面的
                    [href] => 
                )
 
        )
 
    [3] => Array
        (
            [rowbegin] => 
            [rowend] => 
            [0] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 
                    [href] => 
                )
 
        )
 
    [4] => Array
        (
            [rowbegin] => 
            [rowend] => 
            [0] => Array
                (
                    [beginlab] => 
                    [endlab] => 
                    [color] => 
                    [text] => 最后一条
                    [href] => 
                )
        )
 
)

也就是说最里面的数组 如果第一项没有那么就把后面的提到第一项，如果全部没有值 那么就保留第一项。