主题：[求助]遍历整列，计算每行数字与最近的相同数字间的距离

怎么写能同时向上向下遍历计算最短距离啊大佬，我这个写出来不对

Dim t As Table = Tables(“表a")
Dim n As Integer
Dim m As Integer
Dim i As Integer
Dim j As Integer
For i = 0 To t.rows.count-1
    For j  = i+1 To t.rows.count-1
        If t.rows(i)("第一列") = t.rows(j)("第一列") Then
            m = j-i-1
        End If
    Next
    For a As Integer = i-1 To 0
        If t.rows(a)("第一列") = t.rows(i)("第一列") Then
            n= i-a
        End If
    Next
    If m>n Then
        t.Rows(i)("第二列") = m
    Else
        t.Rows(i)("第二列") = n
    End If
Next