Intersecting clickstream data

See the Pen Intersecting Clickstream data by Dhiviya Dhanasekar (@dhiviyadhanasekar) on CodePen.

Two Sum

See the Pen Two-Sum by Dhiviya Dhanasekar (@dhiviyadhanasekar) on CodePen.

Median of an unsorted array

See the Pen Median from arrays by Dhiviya Dhanasekar (@dhiviyadhanasekar) on CodePen.

Jaccard Similarity

# similarity: count(intersection) / count(union)
# arr1 = [3,7,9,12,4...]
# arr2 = [5,9,10,1,2...]

#Case 1
# not sorted
# no duplicates

function computeSimilarity(arr1, arr2){
    
    var map = {};
    var i;
    for(i=0; i < arr1.length; i++){
      map[arr1[i]] = true;
    }
    
    var intersection = 0;
    for(i=0; i < arr2.length; i++){
      var val = arr2[i];
      if(map[val] != null){
          intersection++;
      }
    }
    
    var union = arr1.length + arr2.length - intersection;
    return (intersection/union);
}



# Case 2: sorted arr inputs
# O(n)
# arr1 = [3,7,9,12...]
# arr2 = [5,9,10,...]

function computeSortedSim(arr1, arr2){
    var intersection = 0;
    var i, j;
    for(i =0, j=0; i < arr1.length && j < arr2.length; ){
        if(arr1[i] < arr2[j]) i++;
        else if(arr1[i] > arr2[j]) j++;
        else { i++; j++; intersection++; }
    }
    
    var union = arr1.length + arr2.length - intersection;
    return (intersection/union);
}

Find Duplicate Element

Given: a list of integers where, the integers in the list are in the range 1..n and the list has a length of n+1. Find the duplicate element. The complexity of should be at most O(n).

Link to Code on JSfiddle: https://jsfiddle.net/dhiviyad/zwsan7zt/1/ 

Max Profit

Problem

You are given an array containing prices for a share during a day. The index of the array is the time (in minutes) at which the price of the share had the value at that index. Write a function to return the maximum profit you can get. You can buy the share at any point in time and sell it at any point in time.

Solution

  int[] price = {-1,10,7,6,2};
  
  public int getMaxProfit() {
    
    int min = price[0], maxProfit =0;
    int profit = 0;
    
    for(int i=1; i< price.length; i++) {      
      if(price[i] < min) min = price[i];
      else {
        profit = price[i] - min;
        if(profit > maxProfit) maxProfit = profit;
      }
    }   
    return maxProfit;
  }