CCPC 2021 Online - E Review: Periodic Prefixes and Congruence Classes
Split each time in a cyclic walk into complete cycles and a position within one cycle, then maintain the earliest arrival time in congruence classes modulo the…
CCPC 2021 Online - F Review: Fixed-Pattern Subsequence DP and Partitioning Contributions
Classify fragrant subsequences by the final h of nunhehheh, count prefix choices with fixed-pattern subsequence DP, then multiply by the nonempty choices of su…
CCPC 2021 Online - H Review: Permutation Boundaries and Sums of Inverse Factorials
Split valid contiguous segments in the full-permutation sequence into those within a permutation and those crossing adjacent permutation boundaries. Count usin…