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ROT13 Cipher
A long time ago, some dude needed to send a letter to his lover but didn’t want the messenger to be reading it. After all, messengers were notorious gossips and if this particular messager knew what was in the letter then the whole of the city would have known by tea time. He couldn’t very…
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Generate Hashtags
Today’s problem was especially difficult. Not because the problem was hard, the problem is a no-brainer. No, it was difficult because I decided to only work in Emacs for these challenges. I do not know the first thing about emacs. To make things even more interesting I also decided I would not be using the…
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Find the first non-repeating character
Today we are given a string of characters, the task is to return the first non-repeating character in the string. For the purposes of repetition upper case and lower case characters are treated as the same character but the returned value must have the correct case. Example If there are no non-repeating characters, then return…
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Determinant
In mathematics, a determinant is a special number that you can calculate for square matrices. It’s special because it is only nonzero if and only if the matrix is invertible and the linear map represented by the matrix is an isomorphism. That’s a lot of big words don’t you think? For today’s problem, we don’t…
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Add function
Today we have a quirky problem that requires knowledge of higher-order functions, recursion, and advanced language features. It’s an add function that returns an adder function. Add Function Problem The problem is to create a function that will add numbers together when called in succession. Example It should chain as many times as we want…
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Wave
Ever been to a football match, your team is playing for all their worth and the crowd is enchanted. Then some drunk guys on the other side of the stadium start shouting “WAVE! WAVE”. All of a sudden the a Mexican wave starts from their end, ripples all the way to where you are and…
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Outliers
Oh boy, this one involved some thinking. The problem is to find the outlier in an array of integers. You are given a list that has a minimum of three elements but can have up to a thousand. The array will always have either all even numbers and exactly one odd number or all odd…
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Expanded Numbers
For today we have a number problem. The idea is to take an integer and return the expanded form. This problem wasn’t particularly difficult or tricky and honestly finding a wrong approach would have been harder than finding two correct approaches. Example Input: 12, Output “10 + 2” Input 42, Output “40 + 2” Expanded…
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Brace Validation
Yesterday I did the valid parentheses problem and came up with two solutions, that worked. One was overthought while the other was simplicity defined. The next logical question one can ask though is what if we now want to do brace validation? I.e. there are more than just brackets? What if we include curly braces{},…
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Valid Parentheses
The scenario is you are given a string of parentheses and are tasked to check if they are valid. The description from codewars: “Write a function that takes a string of parentheses, and determines if the order of the parentheses is valid. The function should return true if the string is valid, and false if…