Radix Sort Algorithm in DSA C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the maximum value in the array for Radix Sort.

DSA C++

int getMax(int arr[], int n) {
    int max = arr[0];
    for (int i = 1; i < n; i++) {
        if (arr[i] [1] max) {
            max = arr[i];
        }
    }
    return max;
}

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

A>

B<

C==

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' causes the max to never update correctly.

We compare each element with the current max and update max if the element is greater.

2fill in blank

medium

Complete the code to count the occurrences of digits for the current place value in Counting Sort used by Radix Sort.

DSA C++

void countSort(int arr[], int n, int exp) {
    int output[n];
    int count[10] = {0};

    for (int i = 0; i < n; i++) {
        count[(arr[i] / [1]) % 10]++;
    }
    // rest of the code...
}

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

Aexp

Barr[i]

Cn

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Using 10 instead of exp will always count the units digit only.

We divide by the current exponent (place value) to isolate the digit we want to count.

3fill in blank

hard

Fix the error in the loop that builds the output array in Counting Sort for Radix Sort.

DSA C++

for (int i = n - 1; i >= 0; i--) {
    output[count[(arr[i] / exp) % 10] [1]] = arr[i];
    count[(arr[i] / exp) % 10]--;
}

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

A+

B-

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' will cause index overflow and incorrect placement.

We decrement the count after placing the element to update the position for the next occurrence.

4fill in blank

hard

Fill both blanks to copy the output array back to the original array after Counting Sort step.

DSA C++

for (int i = 0; i [1] n; i++) {
    arr[i] = [2][i];
}

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

A<

B<=

Coutput

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' causes out-of-bounds error.

Copying from count instead of output causes wrong data.

We loop from 0 to less than n and copy each element from output to arr.

5fill in blank

hard

Fill all three blanks to complete the main Radix Sort loop that calls Counting Sort for each digit place.

DSA C++

void radixSort(int arr[], int n) {
    int m = getMax(arr, n);

    for (int exp = 1; exp [1] m; exp = exp [2] 10) {
        countSort(arr, n, [3]);
    }
}

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

A>

B*

Cexp

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '<=' causes the loop to never run.

Passing m instead of exp to countSort causes wrong sorting.

We loop while exp is less than or equal to max, multiply exp by 10 each time, and pass exp to countSort.