##### Welcome to Subscribe On Youtube

Formatted question description: https://leetcode.ca/all/2534.html

# 2534. Time Taken to Cross the Door

## Description

There are `n`

persons numbered from `0`

to `n - 1`

and a door. Each person can enter or exit through the door once, taking one second.

You are given a **non-decreasing** integer array `arrival`

of size `n`

, where `arrival[i]`

is the arrival time of the `i`

person at the door. You are also given an array ^{th}`state`

of size `n`

, where `state[i]`

is `0`

if person `i`

wants to enter through the door or `1`

if they want to exit through the door.

If two or more persons want to use the door at the **same** time, they follow the following rules:

- If the door was
**not**used in the previous second, then the person who wants to**exit**goes first. - If the door was used in the previous second for
**entering**, the person who wants to enter goes first. - If the door was used in the previous second for
**exiting**, the person who wants to**exit**goes first. - If multiple persons want to go in the same direction, the person with the
**smallest**index goes first.

Return *an array *`answer`

* of size *`n`

* where *`answer[i]`

* is the second at which the *`i`

^{th}* person crosses the door*.

**Note** that:

- Only one person can cross the door at each second.
- A person may arrive at the door and wait without entering or exiting to follow the mentioned rules.

**Example 1:**

Input:arrival = [0,1,1,2,4], state = [0,1,0,0,1]Output:[0,3,1,2,4]Explanation:At each second we have the following: - At t = 0: Person 0 is the only one who wants to enter, so they just enter through the door. - At t = 1: Person 1 wants to exit, and person 2 wants to enter. Since the door was used the previous second for entering, person 2 enters. - At t = 2: Person 1 still wants to exit, and person 3 wants to enter. Since the door was used the previous second for entering, person 3 enters. - At t = 3: Person 1 is the only one who wants to exit, so they just exit through the door. - At t = 4: Person 4 is the only one who wants to exit, so they just exit through the door.

**Example 2:**

Input:arrival = [0,0,0], state = [1,0,1]Output:[0,2,1]Explanation:At each second we have the following: - At t = 0: Person 1 wants to enter while persons 0 and 2 want to exit. Since the door was not used in the previous second, the persons who want to exit get to go first. Since person 0 has a smaller index, they exit first. - At t = 1: Person 1 wants to enter, and person 2 wants to exit. Since the door was used in the previous second for exiting, person 2 exits. - At t = 2: Person 1 is the only one who wants to enter, so they just enter through the door.

**Constraints:**

`n == arrival.length == state.length`

`1 <= n <= 10`

^{5}`0 <= arrival[i] <= n`

`arrival`

is sorted in**non-decreasing**order.`state[i]`

is either`0`

or`1`

.