Time needed to buy tickets

Array Queue Simulation

72.2% acceptance

Feb 25, 2026

1890

168

There are n people in a line queuing to buy tickets, where the 0th person is at the front of the line and the (n - 1)th person is at the back of the line. You are given a 0-indexed integer array tickets of length n where the number of tickets that the ith person would like to buy is tickets[i]. Each person takes exactly 1 second to buy a ticket. A person can only buy 1 ticket at a time and has to go back to the end of the line (which happens instantaneously) in order to buy more tickets. If a person does not have any tickets left to buy, the person will leave the line. Return the time taken for the person initially at position k (0-indexed) to finish buying tickets.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn time_required_to_buy(tickets: Vec<i32>, k: i32) -> i32 {
    let k = k as usize;
    let tk = tickets[k];
    tickets.iter().enumerate().map(|(i, &t)| {
      if i <= k {
        t.min(tk)
      } else {
        t.min(tk - 1)
      }
    }).sum()
  }
}