#3 Contains Duplicate. Blind 75. Array

#3 Contains Duplicate. Blind 75. Array

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.

Example 1:

Input: nums = [1,2,3,1]
Output: true

Real world application:

As this is very simple algorithm which runs on linear time.

There are a-lot of variations which can be used in the real world for following :

1. Web Crawling and Indexing:
2. Search engines like Google need to detect and eliminate duplicate web pages to provide unique and relevant search results to users.
3. Fraud Detection:
4. In financial applications, this algorithm can be used to detect fraudulent activities by identifying duplicate transactions or account numbers.
5. Recommendation Systems:
6. In recommendation algorithms, this algorithm can be used to ensure that recommended items are unique and not duplicates of items the user has already seen or purchased.
7. Bioinformatics:
8. In bioinformatics, this algorithm can be used to identify duplicate DNA sequences or protein patterns, which can be important for understanding genetic variations and identifying unique biomarkers.
9. Duplicate File Detection:
10. In file management and storage systems, this algorithm can be used to identify and remove duplicate files, freeing up storage space and improving data organization.

Now let's see how we can solve it:

1 Brute force approach:

function bruteForce(nums){

  for(i = 0; i < nums.length; i++){

    for(let j = i+1; j < nums.length; j++){

      if(nums[i] === nums[j]){

        return true

      }

    }

  }

  return false

}

now nested loops can be optimised in linear time trading space.

This optimisation is very similar to two sum question, where we used a hashMap to optimize. Similary here:

function dupsDetector(nums){

  let map = {}

  for(let index = 0; index < nums.length; index++){

    // if number is dup, return true

    // else go on adding to map

    if(map[nums[index]]){

      return true

    }

    map[nums[index]] = true

  }

  return false

}

This is how the problem can be solved.

#blind75 #softwareengineering #datastructure #FANG