DSA - 2 Problems - Counting Bits, Trie Design

338. Counting Bits

Insight: For each i, use bit manipulation — check last bit using &, right shift », increment count. Can be written in one line. Use memoization to avoid repeated calculations.

Comment: Thought of 2 solutions — bit manipulation and JS inbuilt (string conversion).

221. Design Add and Search Words Data Structure

Insight: Standard Trie. For ‘.’, assume any char → DFS + backtracking.

Comment: Logic was clear, almost solved. Hesitated on implementing ‘.’ DFS (passing root vs node), though idea was there.

Reflection:

• Overall, a decent day.
• Went through URL shortener video