Thirty Days to Hard

Learn C++ and LeetCode-hard problem solving at the same time. Each day is three C++ lessons, one pattern playbook, a four-question quiz, and three timed checkpoints — about two hours.

• Recognition, not recall

  Every playbook is a list of what you see on the page and what it tells you to reach for.

• The judgement call

  What to key the map by, what to sort the intervals by, what the DP state is — the part where people actually stall.

• Timed, and honest

  Miss a checkpoint and it queues for you to re-solve from scratch. Attempting counts; only reading the solution does not.

Already have progress in the standalone version? Import it.