DSA.13.02 Mid-levelCore — asked often

JSON traversal and transformation

Comes up in: DSA, Coding

This concept is being written. It gets the full five steps — explanation, predict, interview angle, practice with tests, and review cards. Here is exactly what it will cover, so you can study it elsewhere in the meantime.

What it covers

recursive traversal of nested objects/arrays
flatten/unflatten
diffing two JSON objects
finding paths to a value
array to tree (parentId → children) and tree to array
cycle-safe traversal

Words you will know

JSON treediff

What you will practise

json-diff (M)
array-to-tree (M)
find-all-paths-to-value (M)
nested-comments-count (E)

Interview questions this answers

Convert a flat list of items with parentId into a tree.
Compute the difference between two JSON objects.