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Combinatorics & Counting

Counting, recursion, generating functions, DP.

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Coupon collector: when does the last coupon arrive?
untried
recommend Linearity of expectation: decompose, then sum +1 more first
Inclusion-exclusion: fix the over-counting by alternating
untried
recommend Complement: when 'not the thing' is easier first
Monte Carlo variance reduction: antithetic and control variates
untried
recommend Central Limit Theorem: turn a sum into a Normal +3 more first
Pólya's urn: exchangeability beats enumeration
untried
recommend Conditional probability: shrinking the sample space first
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Recursion: relate the big problem to a smaller copy
recommended next
Dynamic programming: memoize the overlapping subproblems
untried
recommend Recursion: relate the big problem to a smaller copy first
Generating functions: turn counting into coefficient extraction
untried
recommend Recursion: relate the big problem to a smaller copy first