Sign in
Skip to solution
mediumDSA

What is the sliding window technique?

213 views
01

Understand the problem

Explain sliding window.

sliding-window
02

Attempt it yourself

Sketch your approach before reading the solution — that's what interviews test.

Nudge consolestandby

Stuck? Beam a request up — the console returns a conceptual nudge that guides your logic without spoiling the implementation.

03

Study the solution

Sliding window maintains a contiguous range over an array/string, expanding and shrinking it to satisfy a constraint — turning many O(n²) substring/subarray problems into O(n). Examples: longest substring without repeating characters, max sum of size-k window.

Solution ready — 2 min read

Classified // press E to declassify

04

Read the code

Max sum of a fixed window
Run Playground
def max_window_sum(arr, k):
    window = sum(arr[:k])
    best = window
    for i in range(k, len(arr)):
        window += arr[i] - arr[i - k]   # add new, drop old
        best = max(best, window)
    return best


# --- demo ---
print(max_window_sum([1, 4, 2, 9, 3, 5, 1], 3))   # 17  -> [9,3,5]
05

Join the discussion

Discussion (0)

Sign in to join the discussion.

No responses yet. Be the first to share what you think.

Transmission complete // awaiting log

KEEP THE
STREAK ALIVE.

Dossier 90 of 127 decoded in the Data Structures & Algorithms track. One more won't hurt.

Back to track