Sliding Window Maximum Using Deque in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the deque index for the first element.

DSA C

deque[0] = [1];

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A0

B1

C-1

Dn

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 instead of 0 for the first index.

Initializing deque with -1 which is invalid index.

The deque should start with the index 0 of the first element.

2fill in blank

medium

Complete the condition to remove indices from the back of the deque if current element is greater.

DSA C

while (rear >= front && arr[i] [1] arr[deque[rear]]) {
    rear--;
}

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A<=

B<

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' causing wrong removals.

Using '>=' which may remove equal elements unnecessarily.

We remove from the back while current element is greater than elements at those indices.

3fill in blank

hard

Fix the error in the condition to remove indices out of the current window from the front.

DSA C

if (deque[front] [1] i - k + 1) {
    front++;
}

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

A<

B<=

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' removes valid indices too early.

Using '>=' or '>' reverses the logic.

We remove indices strictly less than the window start index.

4fill in blank

hard

Fill both blanks to correctly assign the maximum for the current window and update the deque.

DSA C

max_values[i - k + 1] = arr[deque[[1]]];
deque[++rear] = [2];

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Afront

Brear

Ci

Dk

Attempts:

3 left

💡 Hint

Common Mistakes

Using rear instead of front for max index.

Adding wrong index to deque.

Maximum is at deque front; add current index i to deque rear.

5fill in blank

hard

Fill all three blanks to complete the sliding window maximum function using deque.

DSA C

for (int i = 1; i < n; i++) {
    while (rear >= front && arr[i] [1] arr[deque[rear]]) {
        rear--;
    }
    deque[++rear] = [2];
    if (deque[front] [3] i - k + 1) {
        front++;
    }
    if (i >= k - 1) {
        max_values[i - k + 1] = arr[deque[front]];
    }
}

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

A>

Bi

C<

Dfront

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operators causing incorrect deque updates.

Adding wrong index to deque.

Incorrect condition to remove out-of-window indices.

Remove smaller elements with '>'; add current index i; remove indices less than window start with '<'.