overlap interval - 1/20/2018 mock interview

OpenInterval_mockInterview.cs

using System;

class Solution
{
    public static int[] MeetingPlanner(int[,] slotsA, int[,] slotsB, int dur)
    {
      if(slotsA == null || slotsA.GetLength(0) < 1 || slotsA.GetLength(1) < 2 ||
         slotsB == null || slotsB.GetLength(0) < 1 || slotsB.GetLength(1) < 2 ||
         dur < 1)
      {
           return new int[0]; 
      }
      
       var lengthA = slotsA.GetLength(0); // 3
       var lengthB = slotsB.GetLength(0); // 2
      
       int indexA = 0; 
       int indexB = 0; 
      
       while(indexA < lengthA && indexB < lengthB)
       {
         // int[], startValue, endValue, 
         var overlapInterval = getIntervalOverlap(slotsA, slotsB, indexA, indexB); 
         
         var start = overlapInterval[0];
         var end   = overlapInterval[1];
         
         if(end - start >= dur)
         {
           return new int[]{start, start + dur};
         }
         else if(slotsA[indexA, 1] >= slotsB[indexB, 1])
         {
           indexB++; 
         }
         else 
         {
           indexA++; 
         }
       }
      
       return new int[0]; 
    }
    
    private static int[] getIntervalOverlap(int[,] slotsA, int[,] slotsB, int indexA, int indexB)
    {
      var maxStart = Math.Max(slotsA[indexA, 0], slotsB[indexB, 0]); 
      var minEnd   = Math.Min(slotsA[indexA, 1], slotsB[indexB, 1]); 
      
       return new int[]{maxStart, minEnd}; 
    }
  
    static void Main(string[] args)
    {

    }
}

/*
series A - interval - not overlap, sorted by start time 

given two seriese, find first overlap matching given duration 8,  for example, [60, 68]

     10         50    60         120   140             210
     ____________     _____________    __________________

0      15             60    70
_______               _______




    10         50    
     ____________    

0      15             
_______              

max(start1, start2)
min(end1, end2)

advance the pointer with less end value 

try to avoid two many if statement. 4 cases

case 1: 
 ________________
     _________
     
case 2: 
    ________________
 __________________________
 
Time complexity: O(m + n), m, n is length of series
space: O(1)

*/