Linear Search Algorithm in DSA Javascript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the index of the target if found, or -1 if not found.

DSA Javascript

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

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Atarget

Bi

Carr

Dlength

Attempts:

3 left

💡 Hint

Common Mistakes

Using the loop index i instead of the target for comparison.

Comparing arr[i] with arr instead of target.

The code compares each element arr[i] with the target value to find a match.

2fill in blank

medium

Complete the code to search through the array and return true if the target exists.

DSA Javascript

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

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Atarget.length

Barr

Ci.length

Darr.length

Attempts:

3 left

💡 Hint

Common Mistakes

Using target.length which is incorrect because target is a value, not an array.

Using arr instead of arr.length in the loop condition.

The loop must run from 0 to arr.length to check every element.

3fill in blank

hard

Fix the error in the code to correctly perform linear search and return the index or -1.

DSA Javascript

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

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Aarr.length

Barr.length + 1

Carr.length - 1

Di.length

Attempts:

3 left

💡 Hint

Common Mistakes

Using arr.length causes index out of range error.

Using arr.length + 1 causes runtime error.

The loop should run while i is less than or equal to arr.length - 1 to avoid going out of bounds.

4fill in blank

hard

Fill both blanks to create a function that returns the index of the target or -1 if not found.

DSA Javascript

function search(arr, target) {
  for (let i = 0; i [1] arr.length; i++) {
    if (arr[i] [2] target) {
      return i;
    }
  }
  return -1;
}

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A<

B<=

C===

D!==

Attempts:

3 left

💡 Hint

Common Mistakes

Using <= in the loop condition causes out of bounds error.

Using !== instead of === in the if condition.

The loop runs while i is less than arr.length, and inside the loop, we check if arr[i] equals the target.

5fill in blank

hard

Fill all three blanks to create a function that returns true if the target is found, false otherwise.

DSA Javascript

function exists(arr, target) {
  for (let [1] = 0; [2] < arr.length; [3]++) {
    if (arr[i] === target) {
      return true;
    }
  }
  return false;
}

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Ai

Dj

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names in loop parts causes errors.

Using 'j' in one part and 'i' in others causes reference errors.

The loop variable is 'i' used consistently in initialization, condition, and increment.