DSA - 1 new, 2 revision (Hashing, Linked List, Strings)

📌 Today’s Progress

1 New • 2 Revisions

New Problem

49. Group Anagrams
Insight: Sort characters of each word and use it as a key in a hashmap to group anagrams.
Comment: Easy overall, but needed a hint to recall the sorting trick.

Observation (JS Quirk):

• arr.sort() sorts alphabetically (case-sensitive) by default
• For numbers → (a, b) => a - b works
• For alphabets → direct sort works, comparator logic differs

Revisions

21. Merge Two Sorted Lists
Insight:
Used standard linked list template:

• dummy, curr, and head pattern
• Traverse using curr
• Return dummy.next
• Append remaining nodes after one list ends

Comment: Felt straightforward — template becoming natural.

271. Encode and Decode Strings
Insight:

• Use length prefixing for each string
• Add delimiter between length and string
• Carefully handle empty strings and edge cases
• Pointer movement is key

Comment: Getting more comfortable managing pointers and parsing logic.

💭 Reflection

Good, productive day overall.
Balanced problem-solving with understanding patterns instead of just solving.

Had the mid-sem dissertation viva — went well, and the progress so far feels solid.
Got an interesting push from the examiner to write a research paper based on this work.

That’s something worth exploring seriously.

Momentum is building ⚡