Day 6: Wait for It


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FAQ

  • bamboo@lemmy.blahaj.zone
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    11 months ago

    Not sure if it’s the most optimal, but I figured it’s probably quicker to calculate the first point when you start winning, and then reverse it to get the last point when you’ll last win. Subtracting the two to get the total number of ways to win.

    Takes about 3 seconds to run on the real input

    Python Solution
    class Race:
        def __init__(self, time, distance):
            self.time = time
            self.distance = distance
    
        def get_win(self, start, stop, step):
            for i in range(start, stop, step):
                if (self.time - i) * i > self.distance:
                    return i
    
        def get_winners(self):
            return (
                self.get_win(0, self.time, 1),
                self.get_win(self.time, 0, -1),
            )
    
    race = Race(71530, 940200)
    winners = race.get_winners()
    print(winners[1] - winners[0] + 1)