TopCoder problem "Quipu" used in SRM 155 (Division II Level One)

Problem Statement


The Incas used a sophisticated system of record keeping consisting of bundles of knotted cords. Such a bundle of cords is called a quipu. Each individual cord represents a single number. Surprisingly, the Incas used a base-10 positional system, just like we do today. Each digit of a number is represented by a cluster of adjacent knots, with spaces between neighboring clusters. The digit is determined by the number of knots in the cluster. For example, the number 243 would be represented by a cord with knots tied in the following pattern

where each uppercase 'X' represents a knot and each '-' represents an unknotted segment of cord (all quotes for clarity only).

Unlike many ancient civilizations, the Incas were aware of the concept of zero, and used it in their quipus. A zero is represented by a cluster containing no knots. For example, the number 204003 would be represented by a cord with knots tied in the following pattern

        ^^    ^^^
        ^^    ^^^
        ^^    two zeros between these three segments
        one zero between these two segments
Notice how adjacent dashes signal the presence of a zero.

Your task is to translate a single quipu cord into an integer. The cord will be given as a String knots containing only the characters 'X' and '-'. There will be a single '-' between each cluster of 'X's, as well as a leading '-' and a trailing '-'. The first cluster will not be empty.



Method signature:int readKnots(String knots)
(be sure your method is public)


-knots contains between 3 and 50 characters, inclusive.
-knots contains only the characters 'X' and '-'. Note that 'X' is uppercase.
-The first and last characters of knots are '-'s. The second character is 'X'.
-knots does not contain 10 consecutive 'X's.
-knots will represent a number between 1 and 1000000, inclusive.


Returns: 243
The first example above.
Returns: 204003
The second example above.
Returns: 1
Returns: 1000000
Returns: 909979

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lbackstrom , brett1479

Problem categories:

String Parsing