First round: I was asked to reverse a linked list in place. Second round: Aman wants to travel across a series of cities, one city per day. You are given an array powerRequired[] of length n, where powerRequired[i] represents the minimum power required to travel on day i. Aman starts his journey with initial power k. Each day, he has two choices: Travel: If Aman current power is greater than or equal to powerRequired[i], he can travel to the next city. This consumes 1 unit of power. He moves to the next day (i + 1). Rest: He can choose to rest instead of traveling. This increases his power by 1 unit. The day does not advance (i remains the same). Your task is to determine the minimum number of total days (including rest days) required for Aman to complete his journey across all n cities. Third round: Implement a data structure where one can search words with prefixes.
