<div class="problems_problem_content__Xm_eO"><p><span style="font-size:18px">Given arrival and departure times of all trains that reach a railway station. Find the minimum number of platforms required for the railway station so that no train is kept waiting.<br>

Consider that all the trains arrive on the same day and leave on the same day. Arrival and departure time can never&nbsp;be the same for a train&nbsp;but we can have arrival time of one train equal to departure time of the other.&nbsp;At any&nbsp;given instance of time, same platform can not be used for both departure of a train and arrival of another train.&nbsp;In such cases,&nbsp;we need different platforms<strong>.</strong></span></p>

<p><br>

<span style="font-size:18px"><strong>Example 1:</strong></span></p>

<pre><span style="font-size:18px"><strong>Input</strong>: n = 6&nbsp;

arr[] = {0900, 0940, 0950, 1100, 1500, 1800}

dep[] = {0910, 1200, 1120, 1130, 1900, 2000}

<strong>Output</strong>: 3

<strong>Explanation</strong>:

Minimum 3 platforms are required to

safely arrive and depart all trains.</span></pre>

<p><span style="font-size:18px"><strong>Example 2:</strong></span></p>

<pre><span style="font-size:18px"><strong>Input</strong>: n = 3

arr[] = {0900, 1100, 1235}

dep[] = {1000, 1200, 1240}

<strong>Output</strong>: 1

<strong>Explanation</strong>: Only&nbsp;1 platform is required to

safely manage the arrival and departure

of all trains.&nbsp;</span>

</pre>

<p><br>

<span style="font-size:18px"><strong>Your Task:</strong><br>

You don't need to read input or print anything. Your task is to complete the function&nbsp;<strong>findPlatform()</strong>&nbsp;which takes the array arr[] (denoting the arrival times), array dep[] (denoting the departure times)&nbsp;and the size of the array as inputs and returns the minimum number of platforms required at the railway station such that no train waits.</span></p>

<p><span style="font-size:18px"><strong>Note:</strong> Time intervals are in the 24-hour format(<strong>HHMM) ,</strong>&nbsp;where the first two characters represent hour (between 00 to 23 ) and the last two characters represent minutes (this may be &gt; 59).</span></p>

<p><br>

<span style="font-size:18px"><strong>Expected Time Complexity:&nbsp;</strong>O(nLogn)<br>

<strong>Expected Auxiliary Space:&nbsp;</strong>O(n)</span></p>

<p><br>

<span style="font-size:18px"><strong>Constraints:</strong><br>

1 ≤ n ≤ 50000<br>

0000 ≤ A[i] ≤ D[i] ≤ 2359</span></p>

</div>