Problem Link:- CodeChef: Practical coding for everyone
Prerequisites:- Binomial theorem, basics of recursion with memoization.
This question is very simple. The above-described pattern forms a Pascal’s Triangle. The T-Shirt no. are the coefficients of the binomial coefficient which forms a pattern in which n increases in the interval of 2 and r increases in an interval of One of n Cr. We can simply sum up the value of all the n Cr/n and multiply it by 2 as the Coefficient on the T-shirt is the same for both sides.
The second part involves setting the obtained value to a precise answer that is setting the decimal value. But we can observe that decimal values will never come when we divide n Cr by n since n directly cancels out the n of the n Cr, therefore the output will always be a Whole number.