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Number of Students Doing Homework at a Given Time - Array - Easy - LeetCode - MiniTV

Number of Students Doing Homework at a Given Time - Array - Easy - LeetCode - मिनी टीवी

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:

using System;
using System.Collections.Generic;
using System.Text;

namespace LeetCode.AskGif.Easy.Array
{
    public class BusyStudentSoln
    {
        public int BusyStudent(int[] startTime, int[] endTime, int queryTime)
        {
            int count = 0;
            for (int i = 0; i < startTime.Length; i++)
            {
                if(startTime[i] <= queryTime && queryTime <= endTime[i])
                {
                    count++;
                }
            }

            return count;
        }
    }
}

 

Time Complexity: O(n)

Space Complexity: O(1)

 

Unit Tests:

using LeetCode.AskGif.Easy.Array;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Text;

namespace CodingUnitTest.Easy.Array
{
    [TestClass]
    public class BusyStudentSolnTests
    {
        [TestMethod]
        public void BusyStudentSoln_First()
        {
            var startTime = new int[] { 1, 2, 3 };
            var endTime = new int[] { 3, 2, 7 };
            var queryTime = 4;
            var output = 1;
            var res = new BusyStudentSoln().BusyStudent(startTime, endTime, queryTime);

            Assert.AreEqual(res, output);
        }

        [TestMethod]
        public void BusyStudentSoln_Second()
        {
            var startTime = new int[] { 4 };
            var endTime = new int[] { 4 };
            var queryTime = 4;
            var output = 1;
            var res = new BusyStudentSoln().BusyStudent(startTime, endTime, queryTime);

            Assert.AreEqual(res, output);
        }

        [TestMethod]
        public void BusyStudentSoln_Third()
        {
            var startTime = new int[] { 1, 1, 1, 1 };
            var endTime = new int[] { 1, 3, 2, 4 };
            var queryTime = 7;
            var output = 0;
            var res = new BusyStudentSoln().BusyStudent(startTime, endTime, queryTime);

            Assert.AreEqual(res, output);
        }

        [TestMethod]
        public void BusyStudentSoln_Fourth()
        {
            var startTime = new int[] { 9, 8, 7, 6, 5, 4, 3, 2, 1 };
            var endTime = new int[] { 10, 10, 10, 10, 10, 10, 10, 10, 10 };
            var queryTime = 5;
            var output = 5;
            var res = new BusyStudentSoln().BusyStudent(startTime, endTime, queryTime);

            Assert.AreEqual(res, output);
        }

        [TestMethod]
        public void BusyStudentSoln_Fifth()
        {
            var startTime = new int[] { 4 };
            var endTime = new int[] { 4 };
            var queryTime = 5;
            var output = 0;
            var res = new BusyStudentSoln().BusyStudent(startTime, endTime, queryTime);

            Assert.AreEqual(res, output);
        }
    }
}