Sliding Window on Arrays in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the window sum with the first k elements.

DSA C

int window_sum = 0;
for (int i = 0; i < [1]; i++) {
    window_sum += arr[i];
}

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

Aarr

Bn

C0

Dk

Attempts:

3 left

💡 Hint

Common Mistakes

Using n instead of k causes summing the whole array.

Using 0 as loop limit results in no iteration.

We sum the first k elements to initialize the sliding window sum.

2fill in blank

medium

Complete the code to slide the window by removing the left element and adding the right element.

DSA C

for (int i = [1]; i < n; i++) {
    window_sum = window_sum - arr[i - k] + arr[i];
    // process window_sum
}

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

Ak

B0

Cn

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Starting from 0 causes incorrect subtraction of elements.

Starting from 1 misses the first full window.

The loop starts from k to slide the window after the initial sum.

3fill in blank

hard

Fix the error in the loop condition to avoid out-of-bounds access.

DSA C

for (int i = k; i <= [1]; i++) {
    window_sum = window_sum - arr[i - k] + arr[i];
}

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

Ak

Bn

Cn - 1

Dn + 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using i <= n causes out-of-bounds access.

Using i <= k limits the loop incorrectly.

Loop should run while i is less than n to avoid accessing arr[n], which is out-of-bounds.

4fill in blank

hard

Fill both blanks to create a sliding window that finds the maximum sum of any window of size k.

DSA C

int max_sum = window_sum;
for (int i = [1]; i <= [2]; i++) {
    window_sum = window_sum - arr[i - k] + arr[i];
    if (window_sum > max_sum) {
        max_sum = window_sum;
    }
}

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Ak

Bn - 1

Cn - k

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using n - k as loop end causes missing last windows.

Starting from 0 causes invalid subtraction.

Loop starts at k and runs until n-1 to cover all windows of size k.

5fill in blank

hard

Fill all three blanks to create a sliding window that stores sums of all windows of size k in an array.

DSA C

int sums[n - k + 1];
sums[0] = window_sum;
for (int i = [1]; i <= [2]; i++) {
    window_sum = window_sum - arr[i - k] + arr[i];
    sums[[3]] = window_sum;
}

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

Ak

Bn - 1

Ci - k + 1

Di

Attempts:

3 left

💡 Hint

Common Mistakes

Using i as index causes out-of-bounds in sums array.

Loop ending before n-1 misses last windows.

Loop starts at k and ends at n-1; sums are stored at index i - k + 1.