Linear scan algorithm - 8:00 pm practice - finish the algorithm around 8 minutes.

LinearScanAlgorithm_practice.cs

using System;

class Solution
{
  public static int FindBusiestPeriod(int[,] data)
  {
    if(data == null || data.GetLength(0) == 0)
      return 0; 
    
    var rows = data.GetLength(0); 
    
    int maxIndex = 0; 
    int maxNumber = 0; 
    
    int currentNumber = 0; 
    for(int row = 0; row < rows; row++)
    {
      int timeStamp = data[row, 0];
      int number    = data[row, 1]; 
      int direction = data[row, 2];  // note: 1 - entrance
    
      currentNumber = direction == 1? (currentNumber + number) : (currentNumber - number); 
      
      var finalState = row == (rows - 1) || timeStamp != data[row + 1, 0]; 
      if(finalState)
      {
        if(currentNumber > maxNumber)
        {
          maxNumber = currentNumber; 
          maxIndex = row; 
        }
      }
    }
    
    return data[maxIndex, 0]; 
  }

  static void Main(string[] args)
  {    	
  }
}

/*
time stamp - multiple entries - 0, 1, 2, first three rows, one time stamp, 
1 -> entrance
0 -> exit
collect all 3 rows -> final state of time stamp -> 14 - 4 - 2 = 8 people left 
Each time stamp final state -> compare maximum number
Linear scan -> determine last row in the current time stamp -> next row, time stamp 
*/