# Query Regarding ZIO

Hi, I want to know, Are we allowed to use computer or to write code and find solution for any given problem in ZIO(1st step for IOI in India), Or we had to solve it using pen and paper itself i.e PC is not allowed at all.

I had seen previous papers and it seems it easy to write recursive function and get answer.

For Eg: Problem 1 from 2017 - Calculate Number of ways of expressing T as the sum of four elements of S. Given Input:S = (1; 3; 2; 1; 1; 3; 4; 2; 2) and T = 8. It would be difficult to do dry run and solve this problem in paper and answer can be even large(in some other problem ans reached till 500). So, Do we had to do it all in paper, if yes. How would you solve this paper, what would be your approach to solve recursive function in paper except doing dry run and find ie totally brute force?

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Well i guess there’s a Calculator available itself in the app. Ask @admin for more details.

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You have a calculator in the app and u are expected to do it manually on paper with help of calculator for calculating. Answer maybe even in thousands. My recommendation is to use something similar to dynamic programming to do recursive functions, calculating previous values and noting them on paper and using them in finding the answer for higher values.

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