(data structure)

**Definition:**
For each position in a *string*, the inverse suffix *array* has its index in the string's *suffix array*.

**Formal Definition:** Given a suffix array, sa, and the corresponding inverse suffix array, isa, isa[i] = j iff sa[j] = i.

**Generalization** (I am a kind of ...)

*array*.

**See also**
*suffix array*.

*Note:
Consider the string "good". In 1-based indexing, the suffix array is [4, 1, 3, 2]. The inverse suffix array is [2, 4, 3, 1]. *

* Many algorithms to build suffix arrays use an inverse suffix array. A suffix array can be built from the inverse suffix array in linear time. An inverse suffix array can be turned into a suffix array in place in linear time, too.*

Author: PEB

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Entry modified 16 November 2016.

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Cite this as:

Paul E. Black, "inverse suffix array", in
*Dictionary of Algorithms and Data Structures* [online], Paul E. Black, ed. 16 November 2016. (accessed TODAY)
Available from: https://www.nist.gov/dads/HTML/inverseSuffixArray.html