It was supposed to be an exploratory call, but it turned out to be a tech screen. The recruiter was very friendly and helpful. There were three questions from HackerRank to solve in 30 minutes.

There are n people standing in line to buy show tickets. Due to high demand, the venue sells tickets according to the following rules:

We represent the initial line of n people as an array, tickets = [ticket(0), ticket(1), ..., ticket(n-1)], where tickets[i] denotes the number of tickets that person i wishes to buy. If Jesse is located at position p, how many seconds will it take for him to purchase his tickets?

For example, if tickets = [1, 2, 5] and p = 1, the first five seconds unfold as follows:

Following rules should apply:

• The person at the head of the line can buy exactly one ticket and must exit the line.
• If a person needs to purchase additional tickets, they must re-enter the end of the line to wait to be sold the next ticket (assume exit and re-entry takes 0 seconds).
• Each ticket sale takes exactly one second.

Find the time taken.