Binary Search vs Linear Search Real Cost Difference in DSA Typescript - Compare & Choose

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of Linear Search on an Unsorted Array

What is the output of the following TypeScript code that performs a linear search for the number 7 in an unsorted array?

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;
}

const array = [3, 1, 4, 7, 5];
console.log(linearSearch(array, 7));

A -1

B 1

C 3

D 4

💡 Hint

Remember linear search checks elements one by one from the start.

The linear search checks each element until it finds 7 at index 3 (0-based). So it returns 3.

❓ Predict Output

intermediate

Output of Binary Search on a Sorted Array

What is the output of the following TypeScript code that performs a binary search for the number 7 in a sorted array?

DSA Typescript

function binarySearch(arr: number[], target: number): number {
  let left = 0;
  let right = arr.length - 1;
  while (left <= right) {
    const mid = Math.floor((left + right) / 2);
    if (arr[mid] === target) {
      return mid;
    } else if (arr[mid] < target) {
      left = mid + 1;
    } else {
      right = mid - 1;
    }
  }
  return -1;
}

const array = [1, 3, 4, 5, 7, 9];
console.log(binarySearch(array, 7));

A 4

B -1

C 3

D 5

💡 Hint

Binary search divides the array and finds the target index.

The number 7 is at index 4 in the sorted array, so binary search returns 4.

🧠 Conceptual

advanced

Cost Difference Between Linear and Binary Search

Which statement best describes the real cost difference between linear search and binary search when searching for an element in a large sorted array?

A Binary search is faster because it reduces the search space by half each step, while linear search checks every element one by one.

B Linear search is faster because it does not require the array to be sorted, unlike binary search.

C Both searches have the same cost because they both look at elements until they find the target.

D Binary search is slower because it requires more comparisons than linear search.

💡 Hint

Think about how many elements each search checks in the worst case.

Binary search cuts the search space in half each time, so it runs in logarithmic time, which is much faster than linear search's checking every element.

❓ Predict Output

advanced

Output of Binary Search on an Unsorted Array

What is the output of the following TypeScript code that performs a binary search for the number 7 on an unsorted array?

DSA Typescript

function binarySearch(arr: number[], target: number): number {
  let left = 0;
  let right = arr.length - 1;
  while (left <= right) {
    const mid = Math.floor((left + right) / 2);
    if (arr[mid] === target) {
      return mid;
    } else if (arr[mid] < target) {
      left = mid + 1;
    } else {
      right = mid - 1;
    }
  }
  return -1;
}

const array = [8, 9, 10, 1, 7];
console.log(binarySearch(array, 7));

A 0

B 2

C 4

D -1

💡 Hint

Binary search requires a sorted array to work correctly.

Since the array is unsorted, binary search cannot reliably find the target and returns -1.

🧠 Conceptual

expert

When Linear Search Can Be More Efficient Than Binary Search

In which scenario can linear search be more efficient than binary search despite binary search's better average time complexity?

A When the array is very large and sorted.

B When the array is very small or the target is near the beginning of the array.

C When the array is sorted and the target is near the end.

D When the array is sorted and contains only unique elements.

💡 Hint

Think about the overhead of binary search and the position of the target.

For small arrays or when the target is near the start, linear search can find the target faster because it checks elements sequentially without overhead.