Excel VBA减去具有相同标签的值

如果单元格有相同的数据包标签，我将做一些关于减去时间值的事情，假设我有如下数据：

| 1  |   A   |  01  |   x   |                  
| 2  |   B   |  03  |   x   |                  
| 3  |   A   |  05  |   x   |                 
| 4  |   C   |  06  |   x   |            
| 5  |   B   |  09  |   x   |  
| 6  |   A   |  11  |   x   |

值应该是这样的：

| 1  |   A   |  01  |   4   | >> Value of subtract time A1 from A3 5-1 = 4  
| 2  |   B   |  03  |   6   | >> Value of subtract time B2 from A5 9-3 = 6   
| 3  |   A   |  05  |   6   | >> Value of subtract time A3 from A6 11-5 = 6 
| 4  |   C   |  06  | value |  
| 5  |   B   |  09  | value |   
| 6  |   A   |  11  | value | 

我目前的代码是：

sub deltaip()

dim x as long
dim i as long

for i = 2 to rows.count
for x = 3 to rows.count

if cells(i,2).value = cells(x,2).value then cells(i,4) = cells(x,3).value-cells(i,3).value

next x
next i

End Sub

但是它被卡住了，我需要让X循环停止，每次它找到相同的值，做减法，然后继续下一个X。我还发现，在下一个i循环中，X不会从3重置，而是从上一个X值开始重置，有什么问题吗

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有人能帮我吗？我对Excel上的VBA非常陌生，提前感谢您通过将更改为Do来完成，就像实际工作表上的代码一样：

Sub deltaip()

Dim x As Long
Dim i As Long
Dim n As Long

n = 3
x = 3

For i = 2 To 11

Do Until Cells(i, 3).Value = Cells(x, 3).Value
x = x + 1
If x > 12 Then Exit Do
Loop

If Cells(x, 2).Value - Cells(i, 2).Value > 0 Then
Cells(i, 8) = Cells(x, 2).Value - Cells(i, 2).Value
Else
Cells(i, 8) = ""
End If

n = n + 1
x = n



Next i

End Sub