Below is a high-yield, pattern-based set of sliding window problems. This covers all core variants:

• fixed vs variable window
• frequency tracking
• distinct constraints
• shrinking conditions
• deque optimization

1. Fixed-Size Window (Simplest Form)

Core Skill

• Maintain window of size k

Problems

• Maximum Average Subarray I
• Find All Anagrams in a String

Pattern

window_sum += nums[r]
if r >= k:
    window_sum -= nums[r-k]

Concepts

• Add right, remove left
• No shrinking logic needed

2. Variable Window (Expand + Shrink)