Performance Issues please help

[PyPK]

>Info req'd for discussing algorithm changes:
>1. How much free memory do you have?

- Memory is not a problem but I am working on some timing
constraints.Thats is the reason I am a bit concerned abt these 30
seconds

> 2. What can you tell us about the distribution of "e"?

    - the distribution of e is not fixed.It changes based on what comes
first in the scan of the list.

> 3. Is "m" a rectangle, or are the rows of variable length?

     - m is not a restnagle .its of varied dimensions.

>  4. Do you have control over "m" i.e. are you stuck with that data
structure, or can we design a different one?

   -I can use 'm' as an array or a list. Other than that I am stuck.

I am suspecious abput dictionary approach here. Is this slower than if
i do it with arrays or lists with index of array as my key ?