[[abstract]]Let T be a text of length n and P be a pattern of length m, both strings over a fixed finite alphabet A. The k-difference (k-mismatch, respectively) problem is to find all occurrences of P in T that have edit distance (Hamming distance, respectively) at most k from P. In this paper we investigate a well-studied case in which T is fixed and preprocessed into an indexing data structure so that any pattern query can be answered faster. We give a solution using an O(nlogn) bits indexing data structure with O(|A|kmk·max(k,logn) +occ) query time, where occ is the number of occurrences. The best previous result requires O(nlogn) bits indexing data structure and gives O(|A|kmk+2+occ) query time. Our solution also allows us to exploit compressed suffix arrays to reduce the indexing space to O(n) bits, while increasing the query time by an O(logn) factor only.
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机译:[[摘要]]令T为长度为n的文本,P为长度为m的模式,两个字符串均位于固定的有限字母A上。k差异(分别为k不匹配)问题是找到所有出现的P在T中具有距P最多k的编辑距离(分别为汉明距离)。在本文中,我们研究了一种经过充分研究的情况,其中T被固定并预处理为索引数据结构,以便可以更快地回答任何模式查询。我们给出一个使用O(nlogn)位索引数据结构和O(| A | kmk·max(k,logn)+ occ)查询时间的解决方案,其中occ是出现的次数。最好的先前结果需要O(nlogn)位索引数据结构,并给出O(| A | kmk + 2 + occ)查询时间。我们的解决方案还允许我们利用压缩后缀数组将索引空间减少到O(n)位,同时仅将查询时间增加O(logn)因子。
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