Calculating lengths of trends

[incblue]

Hi guys, I am completely stumped on this problem. Could anyone help me please?

I am in need of 2 formulae that concern streaks, or trends, of 1s and 0s.
My data is a single column of just 1s or 0s.
For this data, there are two columns that I would like to calculate:

1st column: Rank in trend
If the data cell is the 1st number in the streak, display 1.
If the data cell is the 2nd number in the streak, display 2.
etc etc
The numbers increase until the pattern is broken and a new streak starts, and this column goes back to 1 again.

2nd column: Length of trend
At the start of every streak this column displays how long the streak is.
All cells which are not at the start of a streak should stay blank.

Example Screenshot: (My actual data goes from A1:A40000)

Solutions using standard formulae instead of VBA are preferred in this case.

 

[ZVI]

Hi & welcome to the Board, incblue!

Formula of B2:
=IF(A2=A1,SUM(B1,1),1)

Formula of C2:
=IF(B2=1,IF(B2>=B3,1,INDEX(B2:$B$11,MATCH(1,B3:$B$11,-1))),"")

Copy B2:C2 down

 

[Dryver14]

ZVI

should second formula not read

=IF(B2=1,IF(B2>=B3,1,INDEX(B2:$B$40000,MATCH(1,B3:$B$40000,-1))),"")

 

[ZVI]

The updated formula for C2:
=IF(B2=1,IF(B2>=B3,1,MATCH(1,B3:$B$40000,-1)+ISNA(MATCH(1,B3:$B$40000,0))),"")