I have been doing the Leetcode thing recently, and even became a subscriber to Leetcode.
What I have been doing is I go through the Grind 75 list (Blind 75 successor list), look for the best big O time and space editorial answer, which often has a Java example, and then go to ChatGPT (I subscribe) or Perplexity (don't subscribe to Pro - yet) and say "convert this to Kotlin", which is the language I know best. Jetbrains IDE or Android Studio is capable of doing this, but Perplexity and ChatGPT are usually capable of doing this as well.
Then I say "make this code more compact". Usually I give it some constraints too - keep the big O space and time complexity the same or lower it, keep the function signature of the assigned function the same, and keep the return explicit, make sure no Kotlin non-null assertions crop up. Sometimes I continually have it run these instructions on each version of the iterated code.
I usually test that the code compiles and returns the correct answers for examples after each iteration of compacting. I also copy answers from one to the other - Perplexity to ChatGPT and then back to Perplexity. The code does not always compile, or give the right answers for the examples. Sometimes I overcompact it - what is clear in four lines becomes too confusing in three compacted lines. I'm not looking for the most compact answer, but a clear answer that is as compact as possible.
One question asked about Strings and then later said, what if this was Unicode? So now for String manipulation questions I say assume the String is Unicode, and then at the end say show the answer for ASCII or Unicode. Sometimes the big O time is tricky - it is time O(m+n) say, but since m is always equal to or less than m in the program, it is actually O(n), and both Perplexity and ChatGPT can miss that until it is explained.
People bemoan Leetcode as a waste of time, but I am wasting even less time with it, as ChatGPT and Perplexity are helping give me the code I will be demonstrating in interviews. The common advice I have heard from everywhere is don't waste time trying to figure out the answers myself - just look at the given answers, learn them, and then look for patterns (like binary search problems, which are usually similar), so that is what I am doing.
Initially I was a ChatGPT and Perplexity skeptic for early versions of those sites, in terms of programming, as they stumbled more, but these self-contained examples and procedures they seem well-suited for. Not that they don't hallucinate or give programs that don't compile, or give the wrong answers sometimes, but it saves me time ultimately.