Showing papers in "Journal of Algorithms in 1986"

TL;DR: An invariant of graphs called the tree-width is introduced, and used to obtain a polynomially bounded algorithm to test if a graph has a subgraph contractible to H, where H is any fixed planar graph.

TL;DR: This is the fourteenth edition of a quarterly column that provides continuing coverage of new developments in the theory of NP-completeness, and readers who have results they would like mentioned (NP-hardness, PSPACE- hardness, polynomialtime-solvability, etc.), or open problems they wouldlike publicized, should send them to David S. Johnson.

TL;DR: An algorithm is presented which finds (the size of) a maximum independent set of an n vertex graph in time O (2 0.276 n ) improving on a previous bound of O(2 n 3 ) .

TL;DR: A restriction of the three-dimensional matching problem 3DM, in which the associated bipartite graph is planar, is shown to remain NP -complete.

TL;DR: Klee and Laskowski's O ( n log 2 n ) algorithm for finding all minimal area triangles enclosing a given convex polygon of n vertices is improved to Θ ( n), which is shown to be optimal both forFinding all minima and for finding just one.

TL;DR: It is shown that the depth t and the size s of parallel prefix circuits are related by the inequality t + s ≥ 2n −2, which is true even if arbitrary binary operations can be performed at each node.

TL;DR: An O(n2) space representation for permutation groups of degree n is presented and applications of the representation to the generation of systems of coset representatives, and of complete block systems, are discussed.

TL;DR: This paper shows that if the subnetwork is required to be respectively biconnected and edge-biconconnected, and the underlying network is series-parallel, both problems can be solved in linear time.

TL;DR: The circular case, where the distance between two points is the length of the shortest arc connecting them, is shown to have the same complexity as the simpler linear case.

TL;DR: This paper presents an algorithm to find an edge coloring of a multigraph that never uses more than ⌊ 9 8 χ′ + 3 4 ⌋ colors and runs in O(|E|(|V| + Δ)) time, where E is the set of edges, and V is theSet of vertices.

TL;DR: It is proved that the MULTIFIT scheduling heuristic can be modified, without increasing its time complexity from O(Nlog N), so that its worst-case performance ratio is reduced from some value in the range [1311, 65] to 7261.

TL;DR: A direct relationship between Shellsort and the classical “problem of Frobenius” from additive number theory is used to derive a sequence of O(log N) increments for Shellsort for which the worst case running time is O(N43).

TL;DR: It is shown here that it can generate k bits of an exponentially distributed variate using an average of about k + 5.67974692 coin flippings, which solves a problem left open by Knuth and Yao.

TL;DR: An O ( n 2 ) algorithm is developed to determine whether or not a set of n point pairs can be wired in this manner on a single layer, and it is shown that determining the maximum number of point pairs that can be Wired in with at most one bend is NP-hard.

TL;DR: This paper presents an algorithm for the routing problem for two-terminal nets in generalized switchboxes that solves standard generalized switchbox routing problems in time O ( n (log n ) 2 ) where n is the number of vertices of R, i.e., it either finds a solution or indicates that there is none.

TL;DR: Algorithms for two cases of the polygon containment problem are presented: when both P and P ' are rectilinearly convex, and when P is convex and P " is arbitrary.

TL;DR: It is shown that Ω(n log n) operations are necessary to triangulate a polygonal region with n vertices which contains holes (or windows) and a polynomial time algorithm is presented for partitioning this region into a fixed number of triangles.

TL;DR: This work presents O(n log n) time algorithms for detecting both a C5 or a C6 in a planar graph that uses aPlanar separator that is a small simple cycle.

TL;DR: An O(n log n) time algorithm for computing the convex hull of the n(n − 1)2 points determined by the pairwise intersections of n lines in the plane is given.

TL;DR: An algorithm for the generation of m-ary de Bruijn cycles of length mn is presented, using 3n + kg(n, k) storage, where k is a free parameter in the range 1 ≤ k ≤ m(n−4)2, and g is of order (n − 2logmk)(1 − (1(1 + logmk))).

TL;DR: The randomizing algorithm for the weighted Euclidean 1-center problem is presented and is shown to run on any problem in O(nlogn) time with high probability.

TL;DR: A dynamic programming method for determining the correct value is given, resulting in an algorithm which builds an optimal binary split tree in O ( n 5 ) time for nondistinct access probabilities and Θ ( n 4) time for distinct access probabilities.

TL;DR: This work presents a solution to the following polygon retrieval problem: given a set of n points on the plane, build a data structure so that for any query polygon P the set of points lying in P can be retrieved efficiently.

TL;DR: It is proved that the problem of determining the size of the search space created by a given set of queries and answers is #P-complete and conjecture, based on some preliminary analysis, that the lower bound is Ω(n · log 2 n) .

TL;DR: Bounds on the first two moments of the number of bins used in the packing are established for arbitrary size distributions and these bounds are asymptotically tight.

TL;DR: This paper presents an efficient algorithm that uses the database structure imposed by the way the transactions visit the entities to allow entities to be unlocked before all entities have been locked.

TL;DR: A polynomial-time algorithm is presented for producing a feasible real-valued circulation in undirected graphs with upper and lower bounds, based on Seymour's characterization, which shows that, for mixed graphs, the problem is NP-complete.

TL;DR: A modality-determination algorithm for convex polygons whose running time is linear in the sum of the number of vertices and the total modality of the polygon is given and a connection between modality determination and a range query problem which has received some attention in the Computational Geometry literature is indicated.

TL;DR: It is shown that the cost of threads on deletion is not as high as might be expected, and is especially low for right-threaded trees.