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minimum platforms.cpp
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minimum platforms.cpp
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/*
///////////////////////////////////////////
//Question/Info
Minimum Platforms
Medium Accuracy: 46.78% Submissions: 31238 Points: 4
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.
Consider that all the trains arrive on the same day and leave on the same day. Arrival and departure time can never be the same for a train but we can have arrival time of one train equal to departure time of the other. At any given instance of time, same platform can not be used for both departure of a train and arrival of another train. In such cases, we need different platforms,
Example 1:
Input: n = 6
arr[] = {0900, 0940, 0950, 1100, 1500, 1800}
dep[] = {0910, 1200, 1120, 1130, 1900, 2000}
Output: 3
Explanation:
Minimum 3 platforms are required to
safely arrive and depart all trains.
Example 2:
Input: n = 3
arr[] = {0900, 1100, 1235}
dep[] = {1000, 1200, 1240}
Output: 1
Explanation: Only 1 platform is required to
safely manage the arrival and departure
of all trains.
Your Task:
You don't need to read input or print anything. Your task is to complete the function findPlatform() which takes the array arr[] (denoting the arrival times), array dep[] (denoting the departure times) 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.
Note: Time intervals are in the 24-hour format(HHMM) , where the first two characters represent hour (between 00 to 23 ) and the last two characters represent minutes (between 00 to 59).
Expected Time Complexity: O(nLogn)
Expected Auxiliary Space: O(n)
Constraints:
1 <= n <= 50000
0000 <= A[i] < D[i] <= 2359
Company Tags
Amazon Boomerang Commerce D-E-Shaw Hike Paytm Walmart Zillious Microsoft
author: srj_v
///////////////////////////////////////////
*/
#include <bits/stdc++.h>
using namespace std;
// #define int long long int
#define sbit(x) __builtin_popcount(x)
#define pb(x) push_back(x)
#define mp(x,y) make_pair(x,y)
#define eb(x) emplace_back(x)
#define ct(x) cout << x << "\n";
#define ct2(x,y) cout << x << " " << y << "\n";
#define tc(x) cout << x << " ";
#define tc2(x,y) cout << x << " " << y << " ";
#define forn(i,n) for(int i = 0; i < (int)(n); ++i)
#define forx(i,x,n) for(int i = x; i < (int)(n); ++i)
#define nfor(i,n) for(int i = n-1; i >= 0; --i)
#define all(v) v.begin(),v.end()
#define fsp(x,y) fixed << setprecision(y) << x
#define PI 3.1415926535897932384626433832795
#define MOD 1000000007 // (1e9+7)
#define pii pair<int,int>
#define pis pair<int,string>
#define vi vector<int>
#define vii vector<pii>
#define mii map<int,int>
#define p_q priority_queue // priority_queue<int> (&) priority_queue< int,vi,greater<int> >
#define _IOS ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
typedef long double ld;
typedef long long int lli;
#pragma GCC optimize("Ofast")
void c_p_c()
{
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
}
int32_t main() {
///////////
c_p_c();
///////////
_IOS
//////////
// code
/*
int t ; cin >> t; while(t--){}
*/
class Solution {
public:
//Function to find the minimum number of platforms required at the
//railway station such that no train waits.
int findPlatform(int arr[], int dep[], int n)
{
// Your code here
sort(arr, arr + n);
sort(dep, dep + n);
int max = 1 ;
int p = 1 ;
int i = 1 ; int j = 0;
while (i < n and j < n) {
if (arr[i] <= dep[j])
{
p++;
i++;
if (max < p) {
max = p ;
}
}
else {
j++;
p--;
}
}
return max;
}
};
// cerr << "time: " << clock() << " ms" << '\n';
return 0;
}