Problem

2582. Pass the Pillow

Approach

Math problem — find the pattern. With n people, the period is n-1. Number of full cycles = $\lfloor time / (n-1) \rfloor$. If the number of full cycles is even, the pillow moves forward from the start; otherwise, it moves backward from the end.

Code

class Solution:
    def passThePillow(self, n: int, time: int) -> int:
        if n > time:
            return time + 1
        if time // (n-1) % 2 == 0:
            return time % (n-1) + 1
        else:
            return n - time % (n-1)

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