Abstract
We present optimal parallel solutions to reporting paths between pairs of nodes in an n-node tree. Our algorithms are deterministic and designed to run on an exclusive read exclusive write parallel random-access machine (EREW PRAM). In particular, we provide a, simple optimal parallel algorithm for pre-processing the input tree such that the path queries can be answered efficiently. Our algorithm for preprocessing runs in O(log n) time using O(n/log n) processors. Using the preprocessing, we can report paths between k node pairs in O(log n + log k) time using O(k + (n + S)/log n) processors on an EREW PRAM, where S is the size of the output. In particular, we can report the path between a single pair of distinct nodes in O(log n) time using O(L/log n) processors, where L denotes the length of the path.
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© 1994 Springer-Verlag Berlin Heidelberg
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Maheshwari, A., Lingas, A. (1994). A simple optimal parallel algorithm for reporting paths in a tree. In: Enjalbert, P., Mayr, E.W., Wagner, K.W. (eds) STACS 94. STACS 1994. Lecture Notes in Computer Science, vol 775. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-57785-8_165
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DOI: https://doi.org/10.1007/3-540-57785-8_165
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