Fast Exponentiation Power in Log N in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to multiply the result by x when n is odd.

DSA C

if (n % 2 != 0) {
    result = result [1] x;
}

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

A+

B-

C/

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '*' causes incorrect power calculation.

Using '/' or '-' leads to wrong results or runtime errors.

When n is odd, multiply the current result by x to include the extra factor.

2fill in blank

medium

Complete the code to square x in each iteration.

DSA C

x = x [1] x;

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

A*

B+

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' adds x to itself instead of squaring.

Using '/' or '-' causes wrong calculations.

Squaring x means multiplying x by itself using '*'.

3fill in blank

hard

Fix the error in the loop condition to run while n is greater than zero.

DSA C

while (n [1] 0) {
    // loop body
}

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

A<=

B>

C==

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' causes the loop to never run if n starts positive.

Using '==' runs loop only when n is zero, which is incorrect.

The loop should continue while n is greater than zero to process all bits.

4fill in blank

hard

Fill both blanks to correctly halve n and update the loop.

DSA C

n = n [1] 1;
// loop continues while n [2] 0

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

A>>

B/

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '/' for halving is correct but slower than '>>'.

Using '<' in loop condition causes wrong loop behavior.

Use right shift '>>' to halve n efficiently and '>' to continue loop while n is positive.

5fill in blank

hard

Fill all three blanks to complete the fast exponentiation function.

DSA C

int fastPower(int x, int n) {
    int result = 1;
    while (n [1] 0) {
        if (n & 1) {
            result = result [2] x;
        }
        x = x [3] x;
        n = n >> 1;
    }
    return result;
}

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

A>

B*

C+

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' or '-' instead of '*' breaks power calculation.

Wrong loop condition causes infinite or no loops.

Loop while n > 0, multiply result by x when n is odd, and square x each iteration.