# Leetcode - Number of Students Doing Homework at a Given Time Solution

Given two integer arrays `startTime`

and `endTime`

and given an integer `queryTime`

.

The `ith`

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.
```

**Example 3:**

```
Input: startTime = [4], endTime = [4], queryTime = 5
Output: 0
```

**Example 4:**

```
Input: startTime = [1,1,1,1], endTime = [1,3,2,4], queryTime = 7
Output: 0
```

**Example 5:**

```
Input: startTime = [9,8,7,6,5,4,3,2,1], endTime = [10,10,10,10,10,10,10,10,10], queryTime = 5
Output: 5
```

**Constraints:**

`startTime.length == endTime.length`

`1 <= startTime.length <= 100`

`1 <= startTime[i] <= endTime[i] <= 1000`

`1 <= queryTime <= 1000`

## Solution in Python

```
class Solution:
def busyStudent(self, startTime: List[int], endTime: List[int], queryTime: int) -> int:
return sum(1 for x,y in zip(startTime,endTime) if queryTime>=x and queryTime<=y)
```