Binary Search Recursive Approach in DSA C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to calculate the middle index in the binary search.

DSA C++

int mid = low + ([1] - low) / 2;

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Amid

Bhigh

Clow

Dsize

Attempts:

3 left

💡 Hint

Common Mistakes

Using low twice instead of high and low.

Using size instead of high.

The middle index is calculated using the high and low indices to avoid overflow.

2fill in blank

medium

Complete the code to return the index when the target is found.

DSA C++

if (arr[mid] == target) return [1];

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Alow

B-1

Cmid

Dhigh

Attempts:

3 left

💡 Hint

Common Mistakes

Returning low or high instead of mid.

Returning -1 which means not found.

Return the middle index where the target is found.

3fill in blank

hard

Fix the error in the recursive call for searching the left half.

DSA C++

return binarySearch(arr, low, [1] - 1, target);

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Atarget

Blow

Chigh

Dmid

Attempts:

3 left

💡 Hint

Common Mistakes

Using low or high instead of mid.

Passing target as index.

To search the left half, we reduce the high index to mid - 1.

4fill in blank

hard

Fill both blanks to complete the recursive call for searching the right half.

DSA C++

return binarySearch(arr, [1] + 1, [2], target);

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Amid

Blow

Chigh

Dtarget

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping low and high.

Using target as index.

To search the right half, start from mid + 1 to high index.

5fill in blank

hard

Fill all three blanks to complete the base case and recursive calls of binary search.

DSA C++

if (low > high) return [1];
int mid = low + (high - low) / 2;
if (arr[mid] == target) return [2];
else if (arr[mid] > target) return binarySearch(arr, low, [3] - 1, target);
else return binarySearch(arr, mid + 1, high, target);

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

A-1

Bmid

Dlow

Attempts:

3 left

💡 Hint

Common Mistakes

Returning wrong values in base case or recursive calls.

Using low instead of mid in recursive calls.

Return -1 if not found, return mid if found, and use mid - 1 to search left half.