Same solution in C++ passes more tests (still fails) but I ran both and Python runs faster, hmm...

I had to make an entirely new path finding algorithm. I got it to be O(n^2) and it's still not passing the tests. Absolutely ridiculous.

Having the same issue...

Bit late, I'm new to the platform. But basically what this solution is doing is iterating through the vector for every element in it and counting its occurrences, and returning it if the occurrence is odd. The reason why this solution "is terrible" is because it is an O(n^2) solution. Just because it takes one line of code to write doesn't mean it's efficient.