Array Rotation Techniques in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to rotate the array to the left by one position.

DSA C

void rotateLeftByOne(int arr[], int n) {
    int temp = arr[0];
    for (int i = 0; i < n - 1; i++) {
        arr[i] = arr[i [1] 1];
    }
    arr[n - 1] = temp;
}

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

A/

B-

C*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' instead of '+' causes accessing wrong indices.

Using '*' or '/' operators here is incorrect for indexing.

To shift elements left, each element takes the value of the next element, so we add 1 to the index.

2fill in blank

medium

Complete the code to rotate the array to the right by one position.

DSA C

void rotateRightByOne(int arr[], int n) {
    int temp = arr[n - 1];
    for (int i = n - 1; i > 0; i--) {
        arr[i] = arr[i [1] 1];
    }
    arr[0] = temp;
}

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

A-

B+

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '-' causes accessing wrong indices.

Using '*' or '/' operators here is incorrect for indexing.

To shift elements right, each element takes the value of the previous element, so we subtract 1 from the index.

3fill in blank

hard

Fix the error in the code to rotate the array left by d positions using the reversal algorithm.

DSA C

void reverse(int arr[], int start, int end) {
    while (start < end) {
        int temp = arr[start];
        arr[start] = arr[end];
        arr[end] = temp;
        start++;
        end--;
    }
}

void rotateLeftByD(int arr[], int n, int d) {
    d = d % n;
    reverse(arr, 0, d [1] 1);
    reverse(arr, d, n - 1);
    reverse(arr, 0, n - 1);
}

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

A-

B+

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '-' causes out-of-bound errors.

Using '*' or '/' operators here is incorrect for indexing.

The reversal algorithm reverses the first d elements by reversing from index 0 to d-1, so we subtract 1.

4fill in blank

hard

Fill both blanks to complete the code for rotating the array right by d positions using the reversal algorithm.

DSA C

void rotateRightByD(int arr[], int n, int d) {
    d = d % n;
    reverse(arr, 0, n [1] d - 1);
    reverse(arr, n [2] d, n - 1);
    reverse(arr, 0, n - 1);
}

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

A-

B+

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' in the first blank causes wrong indices.

Using '+' in the second blank causes wrong indices.

To rotate right by d, reverse first n-d elements (0 to n-d-1) and then last d elements (n-d to n-1).

5fill in blank

hard

Fill all three blanks to complete the code for rotating the array left by d positions using the juggling algorithm.

DSA C

int gcd(int a, int b) {
    if (b == 0)
        return a;
    return gcd(b, a [1] b);
}

void rotateLeftByDJuggling(int arr[], int n, int d) {
    d = d % n;
    int g_c_d = gcd(n, d);
    for (int i = 0; i < g_c_d; i++) {
        int temp = arr[i];
        int j = i;
        while (1) {
            int k = j [2] d;
            if (k >= n)
                k = k [3] n;
            if (k == i)
                break;
            arr[j] = arr[k];
            j = k;
        }
        arr[j] = temp;
    }
}

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

A-

B%

C+

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' instead of '%' in gcd.

Using '-' instead of '+' when moving forward in juggling.

Using '+' instead of '-' when wrapping around.

In gcd, use 'a % b' modulo operator. In juggling, add d to j, and if k >= n, subtract n to wrap around.