String Sorting

Years and Authors of Summarized Original Work

• 1997; Bentley, Sedgewick

Problem Definition

The problem is to sort a set of strings into lexicographical order. More formally: A string over an alphabet$\varSigma$is a finite sequence $x_{1}x_{2}x_{3}\ldots x_{k}$where $x_{i} \in \varSigma$fori = 1, …, k.Thex _i s are called the characters of the string, and k is the length of the string. If the alphabet $\varSigma$is ordered, the lexicographical order on the set of strings over $\varSigma$is defined by declaring a string $x = x_{1}x_{2}x_{3}\ldots x_{k}$smaller than a string $y = y_{1}y_{2}y_{3}\ldots y_{l}$if either there exists a j ≥ 1 such that $x_{i} = y_{i}$for 1 ≤ i < j and $x_{j} <y_{j}$or if k < l and $x_{i} = y_{i}$for 1 ≤ i ≤ k. Given a set S of strings over some ordered alphabet, the problem is to sort S according to lexicographical order.

The input to the string sorting problem consists of an array of pointers to the strings to be sorted. The output is a...