- 1
Decisions Over Time
Scheduling DP walks a timeline: at each moment either TAKE the current opportunity and jump past whatever it blocks, or SKIP to the next moment — with phases and sorting to keep the past well-defined.
Complete codeMultiple choice - 2
Stock with Cooldown
A state-machine DP: each day is hold, sold, or rest, and the transitions — especially 'buys come only from rest' — enforce the cooldown that greedy trading skips.
Complete codeDebugMultiple choiceTrace - 3
Minimum Cost For Tickets
DP over the CALENDAR, not the travel list: non-travel days copy dp[d-1] for free, travel days take the cheapest of a 1-, 7-, or 30-day pass reaching back along real dates.
Complete codeMultiple choiceTrace - 4
Solving Questions With Brainpower
Backward DP: taking question i earns its points but jumps you past the questions it blocks, so dp[i] = max(skip, take) must be filled from the end — with a clamp on the jump and a long for the totals.
Complete codeMultiple choiceTrace - 5
Maximum Earnings From Taxi
Weighted interval scheduling on a number line: bucket rides by END point, then dp over positions — drive past empty (dp[p-1]) or finish a ride there (dp[start] + distance + tip). The direct primer for the job-scheduling boss.
Complete codeMultiple choiceTrace - 6
Maximum Length of Pair Chain
Two correct answers, one clear winner: LIS-style DP after sorting by first element works in O(n^2) — but when every interval counts equally, greedy by END point solves it in O(n log n). Learn when scheduling DP collapses to greedy.
Multiple choiceTrace - 7
Scheduling DP CheckpointCheckpoint
No new concepts — the island's take-or-skip-over-time move on unseen ground: gig shifts with rest gaps, a meeting room selling its hours, stock trading with a flat fee, and certification sprints that burn you out.
Complete codeCode orderMultiple choiceTrace - 8
Scheduling DP ReviewReview
Mixed recap of the island: the one take-and-jump-or-skip skeleton behind every mini, when 'what am I holding' joins the state, calendar dp versus event dp, backward fills when takes jump forward, the sort-by-end discipline, and the exact line where greedy stops working.
Complete codeMultiple choice - 9
Boss: Maximum Profit in Job SchedulingBoss
The island's final test: weighted jobs on one timeline. Sort by end, binary-search each job's predecessor, and let one take/skip recurrence price every schedule — while the boss tempts you with count-greedy, start-sorting, and the strict-inequality boundary.
Complete codeDebugCode orderMultiple choiceTrace
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