Sliding Window Technique
Core Mechanism & Implementation
The sliding window technique avoids redundant calculations by keeping track of a subset of elements (the "window") as it moves across an array or string.
🎯 System Scenario & Requirements
System Goal
The sliding window technique avoids redundant calculations by keeping track of a subset of elements (the "window") as it moves across an array or string.
Actors & Components
- Application or API tier
- Core service under design
- Operator or SRE observer
Functional Requirements
- The sliding window technique avoids redundant calculations by keeping track of a subset of elements (the "window") as it moves across an array or string.
- text Window of size K = 3: ┌───┬───┬───┐───┬───┬───┬───┐ │ 2 │ 1 │ 5 │ 1 │ 3 │ 2 │ 9 │ - Sum = 8 └───┴───┴───┘───┴───┴───┴───┘ Slide right: Subtract left (2), Add new right (1) ┌───┌───┬───┬───┐───┬───┬───┐ │ 2 │ 1 │ 5…
- - Window of size K = 3: ┌───┬───┬───┐───┬───┬───┬───┐ │ 2 │ 1 │ 5 │ 1 │ 3 │ 2 │ 9 │ - Sum = 8 └───┴───┴───┘───┴───┴───┴───┘ Slide right: Subtract left (2), Add new right (1) ┌───┌───┬───┬───┐───┬───┬───┐ │ 2 │ 1 │ 5 │ 1…
Constraints & Assumptions
- - Define the Window : Maintain a start and end boundary.
- - Slide : Shift the window to the right by adding the next element and removing the leftmost element.
⚡ Execution Stages & Decision Trace
Stage 1 — Production Considerations & Trade-offs
- Define the Window : Maintain a start and end boundary.
- Slide : Shift the window to the right by adding the next element and removing the leftmost element.
Deep Dive
Scenario context
The sliding window technique avoids redundant calculations by keeping track of a subset of elements (the "window") as it moves across an array or string. ```text Window of size K = 3: ┌───┬───┬───┐───┬───┬───┬───┐ │ 2 │ 1 │ 5 │ 1 │ 3 │ 2 │ 9 │ -> Sum = 8 └───┴───┴───┘───┴───┴───┴───┘ Slide right: Subtract left (2), Add new right (1) ┌───┌───┬───┬───┐───┬───┬───┐ │ 2 │ 1 │ 5 │ 1 │ 3 │ 2 │ 9 │ -> Sum = 7 └───└───……
This walkthrough focuses on Core Mechanism & Implementation.
Before making a design choice, clarify:
- Slide right: Subtract left (2), Add new right (1) ┌───┌───┬───┬───┐───┬───┬───┐ │ 2 │ 1 │ 5 │ 1 │ 3 │ 2 │ 9 │ - Sum = 7 └───└───… This walkthrough focuses on Core Mechanism & Implementation .
- Window of size K = 3: ┌───┬───┬───┐───┬───┬───┬───┐ │ 2 │ 1 │ 5 │ 1 │ 3 │ 2 │ 9 │ - Sum = 8 └───┴───┴───┘───┴───┴───┴───┘ Slide right: Subtract left (2), Add new right (1) ┌───┌───┬───┬───┐───┬───┬───┐ │ 2 │ 1 │ 5 │ 1…
Concepts in play: core-algorithm-patterns, caching
Stage 1 — Production Considerations & Trade-offs
- Define the Window : Maintain a start and end boundary.
- Slide : Shift the window to the right by adding the next element and removing the leftmost element.
- Time Complexity : Reduces time complexity from O(N K) to O(N) .
- Ideal for problems involving contiguous subarrays or substrings (e.g., finding the maximum sum of K consecutive elements, or longest substring with unique characters).
Observable outcome: - Ideal for problems involving contiguous subarrays or substrings (e.g., finding the maximum sum of K consecutive elements, or longest substring with unique characters).
End-to-end outcome
Slide right: Subtract left (2), Add new right (1) ┌───┌───┬───┬───┐───┬───┬───┐ │ 2 │ 1 │ 5 │ 1 │ 3 │ 2 │ 9 │ - Sum = 7 └───└───… This walkthrough focuses on Core Mechanism & Implementation .
Alternatives considered
The source focuses on one primary design. A second architecture is not compared, so no alternative is invented here.
Failure and degraded modes
Production Considerations & Trade-offs
- Detection: - Define the Window : Maintain a start and end boundary.
- User or operator impact: - Define the Window : Maintain a start and end boundary.
Key learnings
- Define the Window : Maintain a start and end boundary.