leetcode

commit 6f6de0dd8860c7fd306bac83ece676c135e615b0
parent 824a9e213577e5b42d87e2753f3a7dbaa5cf8b3b
Author: AndrewLockVI <andrewlaack1@gmail.com>
Date:   Tue, 30 May 2023 21:16:21 -0500

Completed design underground system using dartO

Diffstat:
A
Design-Underground-System/design-underground-system.dart
 | 
50
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1 file changed, 50 insertions(+), 0 deletions(-)
diff --git a/Design-Underground-System/design-underground-system.dart b/Design-Underground-System/design-underground-system.dart
@@ -0,0 +1,50 @@
+//This theoretically has an issue, but in
+//reality the issue is with the question and not my implementation
+//thus I consider this correct as it does what is expected
+//which is tracking entry and exit and finding the average time
+//for a single hop between the two.
+
+//To solve this I created a trip class which just stores where
+//a given user started and at what time. This is placed as the value
+//for the key which is the user's id.
+//Then from here when the user leaves you take the end time - start time
+//and add it to the total time to travel from one station to another along with
+//iterating the total number of trips by 1 to be able to find the mean.
+
+class UndergroundSystem {
+  Map<int, Trip> travelling_users = {};
+  Map<String, List<int>> trip_times = {};
+
+  void checkIn(int id, String stationName, int t) {
+      if(travelling_users.containsKey(id)){
+          return;
+      }
+      travelling_users[id] = new Trip( stationName,t);
+  }
+  
+  void checkOut(int id, String stationName, int t) {
+      Trip current_trip = (travelling_users[id] ?? new Trip('',0));
+      String locations = current_trip.start_name + " " + stationName;
+      List<int> this_trip_time = (trip_times[locations] ?? [0,0]);
+      this_trip_time[0] += 1;
+      this_trip_time[1] += t - current_trip.start_time;
+      trip_times[locations] = this_trip_time;
+  }
+  
+  double getAverageTime(String startStation, String endStation) {
+      List<int> spec_trip = (trip_times[startStation + " " + endStation] ?? []);
+      double average = spec_trip[1] / spec_trip[0];
+      return average;
+  }
+}
+
+
+class Trip{
+    String start_name = "";
+    int start_time = 0;
+    Trip(String _start_name, int _start_time){
+        start_name = _start_name;
+        start_time = _start_time;
+    }
+
+}