Efficiently decoding strings from their shingles
Determining whether an unordered collection of overlapping substrings (called shingles) can be uniquely decoded into a consistent string is a problem that lies within the foundation of a broad assortment of disciplines ranging from networking and information theory through cryptography and even genetic engineering and linguistics. We present three perspectives on this problem: a graph theoretic framework due to Pevzner, an automata theoretic approach from our previous work, and a new insight that yields a time-optimal streaming algorithm for determining whether a string of $n$ characters over the alphabet $Σ$ can be uniquely decoded from its two-character shingles. Our algorithm achieves an overall time complexity $Θ(n)$ and space complexity $O(|Σ|)$. As an application, we demonstrate how this algorithm can be extended to larger shingles for efficient string reconciliation.