checkio | My solutions to the tasks at checkio.org

While the from @Stef and @0x5453 are both relevant to your problem. The comment from @ConnorTJ is patently wrong. The remove function does not remove the item at the index but the first occurrence of the item.

To answer your question, about what's going on here, let[s examine your code: The first pass through the value of x is 1 You print the value of x You then test to see if the number of occurrences of x is less than 2 Since the answer is yes, you proceed to remove the item from the list.

The second pass through the list the For loop picks up the next value in the list (at index 1) which is now the value 3 You print the value 3 You check to see if the count of 3 is less than 2 Since the count is less you remove that item from the list.

This process than continues

Because the index(x) method returns the position of the first value that is equal to x as written in Python documentation, you can find here:

https://docs.python.org/3/tutorial/datastructures.html

so the array.index(84) will return 9 and so it will not be appended to "a".

Use the ignore case regex;

(?i)-ignore or case-insensitive mode ON

Data

data=[

match.toString() doesn't change the value of match variable. You need to return it from the function.

I guess the problem is to find the distribution of the sum of dice. An efficient way to do that is via discrete convolution. The distribution of the sum of variables is the convolution of their probability mass functions (or densities, in the continuous case). Convolution is an n-ary operator, so you can compute it conveniently just two pmf's at a time (the current distribution of the total so far, and the next one in the list). Then from the final result, you can read off the probabilities for each possible total. The first element in the result is the probability of the smallest possible total, and the last element is the probability of the largest possible total. In between you can figure out which one corresponds to the particular sum you're looking for.

The hard part of this is the convolution, so work on that first. It's just a simple summation, but it's just a little tricky to get the limits of the summation correct. My advice is to work with integers or rationals so you can do exact arithmetic.

After that you just need to construct an appropriate pmf for each input die. The input is just [1, 1, 1, ... 1] if you're using integers (you'll have to normalize eventually) or [1/n, 1/n, 1/n, ..., 1/n] if rationals, where n = number of faces. Also you'll need to label the indices of the output correctly -- again this is just a little tricky to get it right.

Convolution is a very general approach for summations of variables. It can be made even more efficient by implementing convolution via the fast Fourier transform, since FFT(conv(A, B)) = FFT(A) FFT(B). But at this point I don't think you need to worry about that.