Problem URL: Find players with zero or one losses

We use 3 different hashset to store zero losses, one loss and more than one loss. Then we iterate through the results array and update the hashsets accordingly. Finally, we iterate through the players array and add the players with zero or one loss to the result.

class Solution:
    def findWinners(self, matches: List[List[int]]) -> List[List[int]]:
        zero, one, more = set(), set(), set()
        for winner, loser in matches:
            if winner not in one and winner not in more:
                zero.add(winner)

            if loser in zero:
                zero.remove(loser)
                one.add(loser)
            elif loser in one:
                one.remove(loser)
                more.add(loser)
            elif loser in more:
                continue
            else:
                one.add(loser)

        return [sorted(list(zero)), sorted(list(one))]

Time complexity: O(nlog(n)), n is the number of matches
Space complexity: O(n)