Grind75

Tasking this out now, as well as timing it.

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What's tough here is the acceptance criteria. It needs to be 3 unique indices and the combination itself needs to be unique. Having the nested 3-loop is cleaner because the variables are in scope. Doing it with the backtracking approach requires cramming data in the recursive function.

dead end. Moving on

The loops are moved around and hidden, but there still seems to be 3 distinct loops. The thing that's interesting (ish) here is that they are treating the problem as an extension of twosum, and re-using that logic, calling a version of twosum inside of 3sum.

I like their algorithm, which looks the two-pointer in the editorial.

I hate when people talk in the library. I can't focus.

This graph problem isn't clicking for me yet (LC 207). Grr. Taking a break.

Attempting that coin change problem again, among other things.

Per the recommendation of several people, I am going to just the Leetcode website to write code. It has the verification and eveything, and will help me pick up on weird edge cases.

39 (combination sum) is a backtracking problem that I am not understanding properly.

I did 46, poorly. 39 passed when I used a different data structure.

Uh oh, I've just been running locally. I've been forgetting to submit stuff. I knew things were feeling wrong.

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Even with the editorial in my face, it still took me an hour to implement. jeez.

Pen and paper

Coding it up

Only took me 2.5 hours.