Computational complexity theory

1 article

1 planar graph 2 satisfiability 3sum Ac Accounting method Addition chain Adversary model Advice Ai complete Algorithmic efficiency All Alloy Amortized analysis Arithmetic circuit complexity Asymptotically optimal algorithm Atomic broadcast Atomic commit Atomix Automatic vectorization Average case complexity Bag Battleship Bend minimization Bidimensionality Big memory Boxicity Boyce codd normal form Cache oblivious algorithm Cache oblivious distribution sort Catalytic computing Cc Certificate Charging argument Circuit value problem Circuits over sets of natural numbers Co re Co re complete Competitive analysis Complete Complexity and real computation Complexity index Computational diffie hellman assumption Computational hardness assumption Computational problem Compute Computer othello Conflict driven clause learning Consensus Constraint logic problem Constraint satisfaction problem Constructible function Counting hierarchy Data lineage Database transaction schedule Decision linear assumption Decisional composite residuosity assumption Decisional diffie hellman assumption Degree constrained spanning tree Deterministic algorithm Diffie hellman problem Dining philosophers problem Discrete logarithm records Distributed concurrency control Distributed graph coloring Dlogtime Dovetailing Dutch national flag problem Dynamic problem Edge matching puzzle Edith clarke Electronic colloquium on computational complexity Element distinctness problem Embarrassingly parallel Empirical algorithmics Entropy compression Envy free item allocation Essential tuple normal form Exponential time hypothesis Failure semantics Fallacies of distributed computing Fixp Fl Flip distance Flow free Fnp Forecasting complexity Formula game Fp Fpt Freecell Fully polynomial time approximation scheme Functional information Funnelsort Game of the amazons Gap reduction Gapp Generalized geography Gi Gi complete Gomoku Half exponential function Hamiltonian completion Hamiltonian decomposition Happened before Hashiwokakero Heyawake Higher residuosity problem Hitori Hitting set Instruction path length Integer circuit Intersection non emptiness problem Ising model K minimum spanning tree Kakuro Karps 21 np complete problems Kernelization Kuromasu L poly Lasertank Lattice problem Lattice protein Lexicographically minimal string rotation Lh Light up Linear arboricity List update problem Logjam Longest palindromic substring Low complexity art Mahjong solitaire Mastermind Masyu Mathematics of paper folding Max 2 sat Max 3lin eqn Max 3sat Maxeksat Maximum inner product search Memory bound function Mendelian error Metric dimension Minesweeper Minimum routing cost spanning tree Multi commodity flow problem Multipartite graph Natarajan dimension Nc Ne Nfa minimization Nl Nl complete Nonelementary problem Nonogram Not all equal 3 satisfiability Np Np hardness Np intermediate Np poly Numberlink Nurikabe Oblivious ram Online matrix vector multiplication problem Output sensitive algorithm Parity p Peg solitaire Phi hiding assumption Phylogenetic reconciliation Pipes Planar sat Planted motif search Pls Polyl Polylogarithmic function Polynomial delay Potential method Ppa Ppad Ppp Pr Probabilistic analysis of algorithms Promise problem Proper complexity function Proportional item allocation Pspace hard Quadrel Rac drawing Re Re complete Reconfiguration Rectangle packing Rectilinear steiner tree Relaxed intersection Resource contention Resource leak Reverse engineering Reversi Ring learning with errors Ring star problem Rotation distance Routing and wavelength assignment Rsa problem Rush hour S2p Samegame Sc Scalability Scale cube Search problem Security level Self dissimilarity Self stabilization Semi membership Separating words problem Set splitting problem Shakashaka Shared register Shared snapshot objects Shikaku Skew symmetric graph Sl Slitherlink Slope number Small set expansion hypothesis Snp Sokoban Sophistication State machine replication State space Stride scheduling String to string correction problem Strong rsa assumption Strongly polynomial time Structural alignment Sub group hiding Subexp Superstabilization Switching circuit theory Tardos function Tatamibari Tc Tc0 Tentai show Terminating reliable broadcast Tetris The art of computer programming The complexity of songs Theta subsumption Thickness Threading Three dimensional edge matching puzzle Timing failure Transdichotomous model Tree alignment Tutte polynomial Uniform consensus Unit disk graph Upward planar drawing Verbal arithmetic Version vector W hierarchy Weft Word representable graph Worst case complexity Xdh assumption Xp

Combinatorics & Discrete Math LycéeExplication9 min

Forty Cubed, Forty Squared, and the Number You Never Choose

A safe takes three numbers from a dial marked 1 to 40, so there are 64,000 combinations, and the worst case is 1600 attempts rather than 64,000. The third number is supplied by the mechanism instead of guessed, which collapses the search from three dimensions to two, and 1600 is proved both achievable and unavoidable. A dial with a mark of mechanical slack drops the count to 196, which is a covering problem on a cycle of forty.