Why Binary Search and What Sorted Order Gives You in DSA C++ - Test Your Knowledge

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start binary search with the middle index.

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

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

2fill in blank

medium

Complete the code to compare the middle element with the target value.

DSA C++

if (arr[mid] [1] target) {

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A<=

B>=

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using inequality instead of equality

Using less than or greater than operators here

We check if the middle element is equal to the target to find it.

3fill in blank

hard

Fix the error in updating the low index when target is greater than middle element.

DSA C++

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

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Amid + 1

Bmid - 1

Clow + 1

Dhigh - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Setting low to mid - 1

Setting low to high - 1

When target is greater, we move low to one position after mid to search the right half.

4fill in blank

hard

Fill both blanks to correctly update high index and return found index.

DSA C++

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

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Amid - 1

Bmid + 1

Cmid

Dlow

Attempts:

3 left

💡 Hint

Common Mistakes

Setting high to mid + 1

Returning low instead of mid

If middle element is greater, we move high to mid - 1 to search left half. If found, return mid index.

5fill in blank

hard

Fill all three blanks to complete the binary search loop and return -1 if not found.

DSA C++

while ([1] <= [2]) {
    int mid = (low + high) / 2;
    if (arr[mid] == target) {
        return [3];
    }
    // other conditions omitted
}
return -1;

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

Alow

Bhigh

Cmid

Dtarget

Attempts:

3 left

💡 Hint

Common Mistakes

Using target in loop condition

Returning low or high instead of mid

The loop runs while low is less than or equal to high. Return mid when target is found.