How to reduce Space Complexity from O(n) to O(1) in DP?

Updated Apr 28, 2026

Short answer

Only store the previous two values instead of an entire array.

Deep explanation

Intermediate Fibonacci techniques focus on Dynamic Programming. Only store the previous two values instead of an entire array.

Real-world example

Caching web service responses to identical queries.

Common mistakes

  • Forgetting to pass the memo object in recursive calls.

Follow-up questions

  • What is the time complexity with memoization?

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