Why Divide and Conquer and What It Gives You in DSA Typescript - Test Your Knowledge

Practice - 5 Tasks

1fill in blank

easy

Complete the code to split the array into two halves.

DSA Typescript

const mid = Math.floor(arr.length [1] 2);

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A+

B*

C/

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or subtraction instead of division.

Using multiplication which increases the length.

We divide the length by 2 to find the middle index for splitting.

2fill in blank

medium

Complete the code to recursively sort the left half of the array.

DSA Typescript

const left = divideAndConquer(arr.slice(0, [1]));

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Amid

Barr.length

C0

Darr.length - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using the full length instead of mid.

Starting slice from mid instead of 0.

We slice the array from 0 to mid to get the left half for recursion.

3fill in blank

hard

Fix the error in the merge function to combine two sorted arrays.

DSA Typescript

while (i < left.length && j [1] right.length) {

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A>

B<

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using greater than which causes skipping the loop.

Using equality which stops early.

We continue merging while both indices are within their array lengths.

4fill in blank

hard

Fill in the blank to compare and merge elements correctly.

DSA Typescript

if (left[i] [1] right[j]) {
  result.push(left[i]);
  i++;
} else {
  result.push(right[j]);
  j++;
}

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A!=

B>

C==

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using equality which does not sort properly.

Using greater than in the wrong place.

We push the smaller element first; if left[i] is less, push it, else push right[j].

5fill in blank

hard

Fill all three blanks to complete the divide and conquer merge sort function.

DSA Typescript

function mergeSort(arr: number[]): number[] {
  if (arr.length <= 1) return arr;
  const mid = Math.floor(arr.length [1] 2);
  const left = mergeSort(arr.slice(0, [2]));
  const right = mergeSort(arr.slice([3]));
  return merge(left, right);
}

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A+

B/

Cmid

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition instead of division for mid.

Incorrect slice indices causing wrong splits.

Divide length by 2 for mid, slice left from 0 to mid, right from mid to end.