# HackerRank Customer Service Capacity

Hi, today I would like to show you how to solve the code puzzle with the timeline. Where you have to in O(n) determine how many maximal events happen simultaneously… I hope you like it ;-). I looked on the Internet, and there is no correct solution for this problem, in my opinion, so far. So I decided to write on my own this solution and share it with my readers… On the Internet, there is one close to work, but it is pretty complex to solve that puzzle efficiently, but I am not 100% sure… The added value of this solution here is the bunch of tests I made… Thanks for reading!

```/*
HackerRank Customer Service Capacity
Problem: Determine how many people need to hire
Input specs:
- the first line contains the current number of customer
service executives
- the second line contains several records in the data set
- the following link contains a pair of timestamps representing
a start of the call and end of the call
Input demo:
1
3
1481222000 1481222020
1481222000 1481222040
1481222030 1481222035
Output demo:
Expected result (number of additional customer service
executives):
1
*/
using System;
using System.Collections.Generic;
namespace CustomerServiceCapacitySandbox
{
class Solution
{
// HackeRank Solution
static int numberOfAgentsToAdd(int numberOfAgents, int[][] callsTimes)
{
var set = new SortedList<int, int>();
for (int i = 0; i < callsTimes.Length; ++i)
{
var b = callsTimes[i][0];
var e = callsTimes[i][1];
if (!set.ContainsKey(b)) set.Add(b, +1); else set[b]++;
if (!set.ContainsKey(e)) set.Add(e, -1); else set[e]--;
}
var max = 0;
var num = 0;
foreach (var val in set.Values)
{
num += val;
if (max < num) max = num;
}
return max - numberOfAgents;
}
static int Test00()
{
var numOfAgent = 1;
var callsTimes = new int[3][];
callsTimes[0] = new int[2];
callsTimes[0][0] = 1481222000;
callsTimes[0][1] = 1481222020;
callsTimes[1] = new int[2];
callsTimes[1][0] = 1481222000;
callsTimes[1][1] = 1481222040;
callsTimes[2] = new int[2];
callsTimes[2][0] = 1481222030;
callsTimes[2][1] = 1481222035;
}
static int Test01()
{
var numOfAgent = 1;
var callsTimes = new int[3][];
callsTimes[0] = new int[2];
callsTimes[0][0] = 1481222000;
callsTimes[0][1] = 1481222020;
callsTimes[1] = new int[2];
callsTimes[1][0] = 1481222001;
callsTimes[1][1] = 1481222040;
callsTimes[2] = new int[2];
callsTimes[2][0] = 1481222002;
callsTimes[2][1] = 1481222035;
}
static int Test02()
{
var numOfAgent = 1;
var callsTimes = new int[3][];
callsTimes[0] = new int[2];
callsTimes[0][0] = 1481222000;
callsTimes[0][1] = 1481222010;
callsTimes[1] = new int[2];
callsTimes[1][0] = 1481222020;
callsTimes[1][1] = 1481222030;
callsTimes[2] = new int[2];
callsTimes[2][0] = 1481222040;
callsTimes[2][1] = 1481222050;
}
static int Test03()
{
var numOfAgent = 1;
var callsTimes = new int[3][];
callsTimes[0] = new int[2];
callsTimes[0][0] = 1481222000;
callsTimes[0][1] = 1481222050;
callsTimes[1] = new int[2];
callsTimes[1][0] = 1481222020;
callsTimes[1][1] = 1481222050;
callsTimes[2] = new int[2];
callsTimes[2][0] = 1481222040;
callsTimes[2][1] = 1481222050;
}
static int Test04()
{
var numOfAgent = 1;
var callsTimes = new int[4][];
callsTimes[0] = new int[2];
callsTimes[0][0] = 1481222000;
callsTimes[0][1] = 1481222050;
callsTimes[1] = new int[2];
callsTimes[1][0] = 1481222020;
callsTimes[1][1] = 1481222050;
callsTimes[2] = new int[2];
callsTimes[2][0] = 1481222040;
callsTimes[2][1] = 1481222050;
callsTimes[3] = new int[2];
callsTimes[3][0] = 1481222050;
callsTimes[3][1] = 1481222060;
}
static int Test05()
{
var numOfAgent = 1;
var callsTimes = new int[4][];
callsTimes[0] = new int[2];
callsTimes[0][0] = 1481222000;
callsTimes[0][1] = 1481222050;
callsTimes[1] = new int[2];
callsTimes[1][0] = 1481222020;
callsTimes[1][1] = 1481222050;
callsTimes[2] = new int[2];
callsTimes[2][0] = 1481222040;
callsTimes[2][1] = 1481222050;
callsTimes[3] = new int[2];
callsTimes[3][0] = 1481222045;
callsTimes[3][1] = 1481222060;
}
static void TestRunner(Func<int> test, int expected)
{
int val = 0;
Console.WriteLine(
test.Method.Name + " = {0} -> {1}",
(val = test.Invoke()), val == expected ? "PASS" : "FAIL");
}
static void Main(string[] args)
{
TestRunner(Test00, 1);
TestRunner(Test01, 2);
TestRunner(Test02, 0);
TestRunner(Test03, 2);
TestRunner(Test04, 2);
TestRunner(Test05, 3);
Console.WriteLine("Press any key to continue...");