Linear Search Algorithm in DSA Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main idea behind the Linear Search Algorithm?

Linear Search checks each item in a list one by one until it finds the target or reaches the end.

beginner

How does Linear Search behave if the target is not in the list?

It checks every item and ends after the last one, returning a result that the target was not found.

intermediate

What is the time complexity of Linear Search in the worst case?

The time complexity is O(n), where n is the number of items in the list, because it may check all items.

beginner

Show a simple JavaScript code snippet for Linear Search.

function linearSearch(arr, target) {
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] === target) {
      return i;
    }
  }
  return -1;
}

beginner

Why is Linear Search not efficient for large lists?

Because it checks each item one by one, it can take a long time if the list is very big.

What does Linear Search do when it finds the target in the list?

A Deletes the target from the list

B Continues checking all items

C Stops and returns the position of the target

D Sorts the list

Linear Search stops as soon as it finds the target and returns its position.

What is the worst-case time complexity of Linear Search?

A O(n log n)

B O(log n)

C O(1)

D O(n)

In the worst case, Linear Search checks every item, so it takes O(n) time.

If the target is not in the list, what does Linear Search return in the example code?

A 0

B -1

C null

D undefined

The example code returns -1 to indicate the target was not found.

Which of these is a key characteristic of Linear Search?

A It checks items one by one

B It requires the list to be sorted

C It uses divide and conquer

D It uses binary splitting

Linear Search checks each item one by one without needing the list to be sorted.

Which data structure is Linear Search best suited for?

A Unsorted lists or arrays

B Hash tables

C Binary trees

D Sorted arrays

Linear Search works well on unsorted lists or arrays where no order is guaranteed.

Explain how Linear Search works step-by-step on a list of numbers.

Think about looking for a name in a list by checking one by one.

Describe the advantages and disadvantages of using Linear Search.

Consider when it is easy to use and when it might be slow.