Abstract
We present a spectrum of randomized time-space tradeoffs for solving directed graph connectivity or STCONN in small space. We use a strategy parameterized by a parameter k that uses k pebbles and performs short random walks of length \(n^{\frac{1}{k}}\) using a probabilistic counter. We use this to get a family of algorithms that ranges between log2 n and log n in space and 2\(^{{\rm log^2}n}\) and n n in running time. Our approach allows us to look at Savitch’s algorithm and the random walk algorithm as two extremes of the same basic divide and conquer strategy.
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Gopalan, P., Lipton, R.J., Mehta, A. (2003). Randomized Time-Space Tradeoffs for Directed Graph Connectivity. In: Pandya, P.K., Radhakrishnan, J. (eds) FST TCS 2003: Foundations of Software Technology and Theoretical Computer Science. FSTTCS 2003. Lecture Notes in Computer Science, vol 2914. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-24597-1_18
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DOI: https://doi.org/10.1007/978-3-540-24597-1_18
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