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

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the middle index in the binary search loop.

DSA C++

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

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A+

B*

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction instead of addition.

Using multiplication instead of addition.

Dividing before adding.

The middle index is calculated by adding low and high, then dividing by 2.

2fill in blank

medium

Complete the code to update the low index when the target is greater than the middle element.

DSA C++

if (arr[mid] < target) {
    low = [1];
}

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Amid + 1

Bmid

Clow + 1

Dhigh

Attempts:

3 left

💡 Hint

Common Mistakes

Setting low to mid instead of mid + 1.

Setting low to high.

Not updating low at all.

When the target is greater than the middle element, we move low to mid + 1 to search the right half.

3fill in blank

hard

Fix the error in the loop condition to correctly run the binary search.

DSA C++

while (low [1] high) {
    int mid = (low + high) / 2;
    // rest of code
}

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

A>

B<=

C>=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using only less than, which misses the last element.

Using greater than or equal, which never runs.

Using greater than, which never runs.

The loop should continue while low is less than or equal to high to cover all elements.

4fill in blank

hard

Fill both blanks to correctly update the high index when the target is less than the middle element.

DSA C++

if (target [1] arr[mid]) {
    high = [2];
}

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A<

B>

Cmid - 1

Dmid + 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using greater than instead of less than in comparison.

Setting high to mid + 1 instead of mid - 1.

Not updating high at all.

If the target is less than the middle element, we move high to mid - 1 to search the left half.

5fill in blank

hard

Fill all three blanks to complete the binary search function that returns the index or -1 if not found.

DSA C++

int binarySearch(int arr[], int size, int target) {
    int low = 0, high = size [1] 1;
    while (low [2] high) {
        int mid = (low + high) / 2;
        if (arr[mid] == target) return [3];
        else if (arr[mid] < target) low = mid + 1;
        else high = mid - 1;
    }
    return -1;
}

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

A-

B<=

Cmid

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Setting high to size instead of size - 1.

Using less than instead of less than or equal in loop.

Returning low or high instead of mid when found.

We set high to size - 1 because array indices start at 0. The loop runs while low is less than or equal to high. When found, return mid index.