Showing papers by "Richard Cole published in 1995"

Tighter Lower Bounds on the Exact Complexity of String Matching

Abstract: This paper considers the exact number of character comparisons needed to find all occurrences of a pattern of length $m$ in a text of length $n$ using on-line and general algorithms. For on-line algorithms, a lower bound of about $(1+\frac{9}{4(m+1)})\cdot n$ character comparisons is obtained. For general algorithms, a lower bound of about $(1+\frac{2}{m+3})\cdot n$ character comparisons is obtained. These lower bounds complement an on-line upper bound of about $(1+\frac{8}{3(m+1)})\cdot n$ comparisons obtained recently by Cole and Hariharan. The lower bounds are obtained by finding patterns with interesting combinatorial properties. It is also shown that for some patterns off-line algorithms can be more efficient than on-line algorithms.

Routing on butterfly networks with random faults

Abstract: We show that even if every node or edge in an N-node butterfly network fails independently with some constant probability, p, it is still possible to identify a set of /spl Theta/(N) nodes between which packets can be routed in any permutation in O(logN) steps, with high probability. Although the analysis as complicated, the routing algorithm itself is relatively simple.

On the Dynamic Finger Conjecture for Splay Trees Part I: Splay Sorting log n-Block Sequences

Abstract: A special case of the Dynamic Finger Conjecture is proved; this special case introduces a number of useful techniques.