In graph theory and theoretical computer science, the level ancestor problem is the problem of preprocessing a given rooted tree T into a data structure that can determine the ancestor of a given node at a given distance from the root of the tree.
More precisely, let T be a rooted tree with n nodes, and let v be an arbitrary node of T. The level ancestor query LA(v,d) requests the ancestor of node v at depth d, where the depth of a node v in a tree is the number of edges on the shortest path from the root of the tree to node v.
It is possible to solve this problem in constant time per query, after a preprocessing algorithm that takes O(n) and that builds a data structure that uses O(n) storage space.[1][2]
^Bender, Michael A.; Farach-Colton, Martin (2004). "The Level Ancestor Problem Simplified". Theor. Comput. Sci. 321: 5–12. doi:10.1016/j.tcs.2003.05.002.
^Berkman, Omer; Vishkin, Uzi (Apr 1994). "Finding level-ancestors in trees". J. Comput. Syst. Sci. 2. 48 (2): 214–230. doi:10.1016/S0022-0000(05)80002-9.
and 26 Related for: Level ancestor problem information
science, the levelancestorproblem is the problem of preprocessing a given rooted tree T into a data structure that can determine the ancestor of a given...
The LCA problem also finds applications in models of complex systems found in distributed computing (Bender et al. 2005). Levelancestorproblem Semilattice...
bacterium came together to create the first eukaryotic common ancestor (FECA). This cell had a new level of complexity and capability, with a nucleus, at least...
in computer science, such as the lowest common ancestorproblem and the longest common prefix problem (LCP). Given an array A[1 … n] of n objects taken...
may cause health problems, which may cause wild ancestors to have longer natural lifespans. Behavioral differences in wild ancestors were caused by differences...
"The fraction of human-level civilizations that reach a posthuman stage (that is, one capable of running high-fidelity ancestor simulations) is very close...
Verbaeten (2004). "A Generalization and Solution to the Common Ancestor Dilemma Problem in Delegation-Based Object Systems" (PDF). Proceedings of the 2004...
Intervals, that "are immune to hierarchy reorganization problem, and allow answering ancestor path hierarchical queries algorithmically — without accessing...
The Cyprus problem, also known as the Cyprus conflict, Cyprus issue, Cyprus dispute, or Cyprus question, is an ongoing dispute between the Greek Cypriot...
The Problem of Pain is a 1940 book on the problem of evil by C. S. Lewis, in which Lewis argues that human pain, animal pain, and hell are not sufficient...
in eukaryotes? Last universal common ancestor. What were the characteristics of the Last Universal Common Ancestor of Archaea, Bacteria, and Eukaryotes...
will). By contrast, a breadth-first (level-order) traversal will traverse a binary tree of infinite depth without problem, and indeed will traverse any tree...
mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known...
pre-arthropod ancestors; for example, all spiders extend their legs hydraulically and can generate pressures up to eight times their resting level. The exoskeleton...
demonstrate specificity Inheritance is a key feature in CSS; it relies on the ancestor-descendant relationship to operate. Inheritance is the mechanism by which...
Mitochondrial-Most Recent Common Ancestor, shortened to mt-Eve or mt-MRCA) is the matrilineal most recent common ancestor (MRCA) of all living humans. In...
genetically engineered by the ruler and first of vampires called Sacred Ancestor using his own DNA and that of humans in an experiment to create a vampire...
avant-garde acts like the Dillinger Escape Plan, Neurosis, Zeni Geva, Ancestors, and Oranssi Pazuzu all cite King Crimson's influence. Other artists affected...
evaluation per cell. Similar problems of task ordering arise in makefiles for program compilation and instruction scheduling for low-level computer program optimization...
The problem of two emperors or two-emperor problem (deriving from the German term Zweikaiserproblem, Greek: πρόβλημα δύο αυτοκρατόρων) is the historiographical...
morphologically distinct form to be considered a different species from its ancestors. Viruses have enormous populations, are doubtfully living since they consist...
recursive definition of a person's ancestor. One's ancestor is either: One's parent (base case), or One's parent's ancestor (recursive step). The Fibonacci...
(gorillas) between 8 and 9 mya; Australopithecine (including the extinct biped ancestors of humans) separated from the Pan genus (containing chimpanzees and bonobos)...
romanized: Shkalá Kardashova) is a method of measuring a civilization's level of technological advancement based on the amount of energy it is capable...
and a new level on that branch. Specifically, also extinct groups are always put on a side-branch, not distinguishing whether an actual ancestor of other...
characteristic of having a kinship with a relative who is descended from a common ancestor. Many jurisdictions have laws prohibiting people who are related by blood...