Please read How to Think Recursively before reading this post. This post re-applies the steps mentioned in the previous post on a more challenging question. Question Return all possible ways we can generate a well-formed parenthesis? Examples: if n = 1 then we can only form () if n = 2 then we can form (()) and ()() if n = 3 then we can form ((())), (())(), ()(()), (()()), (), (), () Let’s try applying our 4 steps:...
These articles are about the gotchas I faced when trying to think recursively. The logic in principle should apply to most recursive problems. In this post, I will use the following question as a point of reference: ‘Count how many ways you can climb a staircase. You can jump either one step at a time or two steps at a time.’ Example if there are 3 stair cases then you can either jump:...
My team was dealing with a large flow, where user can transition from multiple states or sometimes skip certain states. We didn’t have a centralized controller, every screen just had logic on where it should go next. This made it difficult for us to see all our logic at once. We asked around and was told state machines are a good fit for our situation. State machines are void of any UX....
What’s a subsequence? Any selection of items from the original array. The selection must respect the order. Meaning for [1,2,3,4,5] only two of the four below are subsequences: [1,2,3,4,5] ✅ [1,4,3,2,5] ❌ order not respected [1,2,5] ✅ [5,1] ❌ order not respected What’s the difference between a subsequence and a subarray? Subarray, is just like subsequence, that is order must be respected. Additionally the sub-array has to be made of continuous elements....