Communication complexity
Approximate counting of inversions in a data stream
STOC '02 Proceedings of the thiry-fourth annual ACM symposium on Theory of computing
SODA '03 Proceedings of the fourteenth annual ACM-SIAM symposium on Discrete algorithms
Continuously Maintaining Quantile Summaries of the Most Recent N Elements over a Data Stream
ICDE '04 Proceedings of the 20th International Conference on Data Engineering
Estimating the sortedness of a data stream
SODA '07 Proceedings of the eighteenth annual ACM-SIAM symposium on Discrete algorithms
SODA '07 Proceedings of the eighteenth annual ACM-SIAM symposium on Discrete algorithms
FOCS '07 Proceedings of the 48th Annual IEEE Symposium on Foundations of Computer Science
Streaming algorithms with one-sided estimation
APPROX'11/RANDOM'11 Proceedings of the 14th international workshop and 15th international conference on Approximation, randomization, and combinatorial optimization: algorithms and techniques
SIAM Journal on Computing
A note on randomized streaming space bounds for the longest increasing subsequence problem
Information Processing Letters
Edit distance to monotonicity in sliding windows
ISAAC'11 Proceedings of the 22nd international conference on Algorithms and Computation
Tight bounds for distributed functional monitoring
STOC '12 Proceedings of the forty-fourth annual ACM symposium on Theory of computing
Streaming computations with a loquacious prover
Proceedings of the 4th conference on Innovations in Theoretical Computer Science
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In this paper we consider problems related to the sortedness of a data stream. First we investigate the problem of estimating the distance to monotonicity; given a sequence of length n, we give a deterministic (2 + ε)-approximation algorithm for estimating its distance to monotonicity in space O(1/ε2 log2 (εn)). This improves over the randomized (4 + ε)-approximation, algorithm of [3]. We then consider the problem of approximating the length of the longest increasing subsequence of an input stream of length n. We use techniques from multi-party communication complexity combined with a fooling set approach to prove that any O(1)-pass deterministic streaming algorithm that approximates the length of the longest increasing subsequence within 1 + ε requires Ω(√n) space. This proves the conjecture in [3] and matches the current upper bound.