How I'd relearn DSA from zero
Build a toolkit with USACO Guide, then test it on untagged AtCoder problems.
Transcript and practiceVideo lessons
Binary search with Emilia
Find a value in a sorted array, then search for the first feasible answer. Japanese narration with English captions.
Transcript and practiceMo’s algorithm with Waguri
Answer range queries by moving one window and ordering the queries offline.
Transcript and practiceSegment Tree Beats
Use the two largest values in a node to find when a range cap can stop.
Transcript and practiceLearn how to practice DSA
Use deliberate attempts, untagged practice and editorials to examine how you learn.
Transcript and practiceLearn new DSA topics through problems
Use a difference array to turn range updates into a running total, then apply the same idea to overlapping bookings.
Transcript and practiceChoose your DSA practice platform
Where LeetCode, USACO Guide, AtCoder and CSES fit in your preparation, based on the time you have.
Transcript and practiceCount the work in nested loops
Trace a persistent counter and a reset counter. The same nested loops perform 5 or 15 increments when n = 6.
Transcript and practiceDynamic programming: states and transitions
Define a stored answer, establish the Fibonacci base cases, and build later answers from earlier ones. Follow the recurrence and its induction argument.
Transcript and practiceWhen vector growth invalidates pointers
Follow a C++ vector from a full allocation through push_back, pointer invalidation and reserve. Addresses and growth capacity are illustrative.
Transcript and practice
Binary search
Koko Eating Bananas: choose an eating rate
875. Koko Eating Bananas · Medium · 1 min watch
Hints and transcript
Stacks and queues
Valid Parentheses with a stack
20. Valid Parentheses · Easy · 1 min watch
Hints and transcript