2026-05-22

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Daily Prep - Friday, 2026-05-22

Today’s Targets Completed

DSA - 4 Problems

• LC1: Range Sum Query - Immutable (Easy)
• LC2: Find the Middle Index in Array (Easy)
• LC3: Find Pivot Index (Easy)
• LC4: Subarray Sum Equals K (Medium)

System Design - 1 Topic

• Topic: Change Data Capture (CDC)

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End Of Day Reflection

• Shifted to a new pattern today: Prefix Sum! Transitioning from Sliding Window went smoothly.
• Mastered Subarray Sum Equals K by understanding how running prefix sums combined with a Frequency HashMap can reduce the time complexity from $O(N^2)$ to $O(N)$.

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Next Day Goal

• Solve more complex Prefix Sum / Difference Array problems (4 problems).
• Write notes on Prefix Sum pattern index/concepts.

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