Linear Search Algorithm in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the index of the target element in the array or -1 if not found.

DSA Typescript

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

Drag options to blanks, or click blank then click option'

Atarget

Barr.length

Carr[i]

Di

Attempts:

3 left

💡 Hint

Common Mistakes

Using the loop index i instead of the target value.

Comparing the element to itself instead of the target.

The code compares each element arr[i] with the target. So, the blank must be target to check if the current element matches the target.

2fill in blank

medium

Complete the code to return -1 if the target is not found after checking all elements.

DSA Typescript

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

Drag options to blanks, or click blank then click option'

A-1

Bundefined

Cnull

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Returning 0 which is a valid index.

Returning null or undefined which are not numbers.

If the target is not found, the function should return -1 to indicate absence.

3fill in blank

hard

Fix the error in the loop condition to avoid going out of array bounds.

DSA Typescript

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

Drag options to blanks, or click blank then click option'

Ai

Btarget

Carr.length - 1

Darr.length

Attempts:

3 left

💡 Hint

Common Mistakes

Using i <= arr.length which is off by one.

Using target or i in the condition incorrectly.

The loop should run while i < arr.length to avoid accessing an index outside the array.

4fill in blank

hard

Fill both blanks to create a function that returns true if the target exists in the array, false otherwise.

DSA Typescript

function contains(arr: number[], target: number): boolean {
  for (let i = 0; i < [1]; i++) {
    if (arr[i] === [2]) {
      return true;
    }
  }
  return false;
}

Drag options to blanks, or click blank then click option'

Aarr.length

Btarget

Ci

Darr

Attempts:

3 left

💡 Hint

Common Mistakes

Using i or arr as loop limit.

Comparing with i instead of target.

The loop should run while i < arr.length and compare arr[i] with target to check if the target exists.

5fill in blank

hard

Fill all three blanks to create a function that counts how many times the target appears in the array.

DSA Typescript

function countOccurrences(arr: number[], target: number): number {
  let count = 0;
  for (let i = 0; i < [1]; i++) {
    if (arr[i] === [2]) {
      count[3]1;
    }
  }
  return count;
}

Drag options to blanks, or click blank then click option'

Aarr.length

Btarget

C+=

D++

Attempts:

3 left

💡 Hint

Common Mistakes

Using count += 1 is correct but not the expected answer here.

Using wrong loop limit or comparing with wrong variable.

The loop runs while i < arr.length. It compares arr[i] with target. To increase count by one, use count++.