Book Reading Unlock Order
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Book Reading Unlock Order
Bob has n book volumes numbered from 1 to n. To maintain continuity, he can only read volume i after finishing all volumes from 1 to i - 1. Each day, exactly one volume unlocks. The unlocking order is given as a permutation of size n, where the i-th element represents the volume unlocked on day i. For each day, determine how many new volumes Bob can read. If the unlocked volume allows reading multiple consecutive unread volumes, count all of them. Otherwise, output 0.
Examples
2 1 4 3
0 2 0 2
Explanation: On day 2, Bob can read volumes 1 and 2. On day 4, Bob can read volumes 3 and 4.
Approach hint
Keep track of the smallest volume number that Bob has not read yet.
Common mistake
Skipping assumptions, edge cases, or trade-offs can make an otherwise good answer feel incomplete.