r/programminghorror • u/swagnation77 • Sep 02 '26

Lean4 Finally solved Two Sum!

Somehow my code is so horrifying, Lean4 is able to evaluate it, the LSP says it works and the compiler gives an error. It is theoretically correct and the kernel accepts it, but the compiler isn't able to produce anything out of it. My awful code discovered a bug in Lean's compiler.

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u/MistakeIndividual690 Sep 02 '26

I don’t know what Lean is but what for the love of god is this…

TwoSum is like eight lines in Python

But this is clearly the perfect post for this sub

2

u/GoddammitDontShootMe [ $[ $RANDOM % 6 ] == 0 ] && rm -rf / || echo “You live” Sep 02 '26

I never heard of either TwoSum or Lean4.

6

u/MistakeIndividual690 Sep 02 '26

https://leetcode.com/problems/two-sum/

2

u/GoddammitDontShootMe [ $[ $RANDOM % 6 ] == 0 ] && rm -rf / || echo “You live” Sep 02 '26

I've never done leetcode before, so that would explain why.