Find Maximum Subarray Divide and Conquer in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find the middle index of the array segment.

DSA Typescript

const mid = Math.floor((left + [1]) / 2);

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Aright

Bleft

Cmid

Darr.length

Attempts:

3 left

💡 Hint

Common Mistakes

Using left twice instead of left and right.

Using array length instead of right index.

The middle index is calculated by averaging left and right indices.

2fill in blank

medium

Complete the code to return the maximum of three values.

DSA Typescript

return Math.max(leftSum, rightSum, [1]);

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AmidSum

BcrossSum

CtotalSum

DmaxSum

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable not representing crossing sum.

Forgetting to include crossing sum in max calculation.

The maximum subarray sum is the max of left, right, and crossing sums.

3fill in blank

hard

Fix the error in the loop that calculates left crossing sum.

DSA Typescript

for (let i = mid; i >= [1]; i--) { leftSum += arr[i]; maxLeft = Math.max(maxLeft, leftSum); }

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Aleft

B0

Cmid

Dright

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 instead of left index.

Using mid or right incorrectly as loop boundary.

The loop must go down to the left boundary index.

4fill in blank

hard

Fill both blanks to calculate right crossing sum correctly.

DSA Typescript

let rightSum = 0; let maxRight = -Infinity; for (let j = mid + 1; j [1] [2]; j++) { rightSum += arr[j]; maxRight = Math.max(maxRight, rightSum); }

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A<=

B<

Cright

Dleft

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of <= causing missing last element.

Using left instead of right as boundary.

The loop runs from mid+1 up to right index (inclusive).

5fill in blank

hard

Fill all three blanks to complete the recursive maximum subarray function.

DSA Typescript

function maxSubArray(arr: number[], left: number, right: number): number { if (left === right) return [1]; const mid = Math.floor((left + right) / 2); const leftSum = maxSubArray(arr, left, [2]); const rightSum = maxSubArray(arr, [3], right); const crossSum = maxCrossingSum(arr, left, mid, right); return Math.max(leftSum, rightSum, crossSum); }

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Aarr[left]

Bmid

Cmid + 1

Dright

Attempts:

3 left

💡 Hint

Common Mistakes

Returning arr[right] in base case.

Using wrong indices in recursive calls.

Base case returns single element; recursive calls split at mid and mid+1.