NumberOfStudentsDoingHomeworkAtGivenTime.php

<?php

namespace App;

/**
 * Number of Students Doing Homework at a Given Time
 *
 * Given two integer arrays startTime and endTime and given an integer queryTime. The i-th student started doing their
 * homework at the time startTime[i] and finished it at time endTime[i]. Return the number of students doing their
 * homework at time queryTime. More formally, return the number of students where queryTime lays in the interval
 * [startTime[i], endTime[i]] inclusive.
 *
 * Example 1:
 * Input: startTime = [1,2,3], endTime = [3,2,7], queryTime = 4
 * Output: 1
 * Explanation: We have 3 students where:
 * The first student started doing homework at time 1 and finished at time 3 and wasn't doing anything at time 4.
 * The second student started doing homework at time 2 and finished at time 2 and also wasn't doing anything at time 4.
 * The third student started doing homework at time 3 and finished at time 7 and was the only student doing homework
 * at time 4.
 *
 * Example 2:
 * Input: startTime = [4], endTime = [4], queryTime = 4
 * Output: 1
 * Explanation: The only student was doing their homework at the queryTime.
 *
 * https://leetcode.com/problems/number-of-students-doing-homework-at-a-given-time
 */
class NumberOfStudentsDoingHomeworkAtGivenTime
{
    /**
     * @param int[] $startTime
     * @param int[] $endTime
     * @param int $queryTime
     * @return int
     */
    public function busyStudent(array $startTime, array $endTime, int $queryTime): int
    {
        $count = 0;
        foreach ($startTime as $key => $value) {
            if ($value <= $queryTime && $queryTime <= $endTime[$key]) {
                $count++;
            }
        }
        return $count;
    }
}