Number of Students Doing Homework at a Given Time

Problem Description

Given two integer arrays startTime and endTime and an integer queryTime, return the number of students doing their homework at queryTime. More formally, return the number of students where queryTime lays in the interval [startTime[i], endTime[i]] inclusive.

Key Insights

• We need to check each student's homework time interval to see if queryTime falls within it.
• The problem can be solved with a simple loop since the constraints are small, allowing a straightforward O(n) solution.
• We can leverage the fact that both arrays have the same length, simplifying our checks.

Space and Time Complexity

Time Complexity: O(n), where n is the number of students (length of the arrays). Space Complexity: O(1), as we are using a constant amount of extra space.

Solution

To solve this problem, we can iterate through the startTime and endTime arrays simultaneously. For each student, we check if the queryTime falls within their homework interval by verifying if startTime[i] <= queryTime <= endTime[i]. We maintain a count of how many students satisfy this condition.

Code Solutions