TopcoderArchive
Archive30 Jul 2007
TCCC07 Qual 2

BlockCounter

Problem statement, definition, constraints, and public examples.

Problem Statement

You are given a compressed word that is in one of the following three forms:

  1. A single character 'A' or 'B'. In this case, the uncompressed word is equal to the compressed one.
  2. A string formatted as "ST" (quotes for clarity), where S and T are each compressed words. To uncompress a word of this form, uncompress S and T and return their concatenation.
  3. A string formatted as "(X,S)" (quotes for clarity), where X is a digit between 1 and 9, inclusive, and S is a compressed word. To uncompress a word of this form, uncompress S and return the concatenation of X copies of that uncompressed word.

For example, "(2,A(3,AB))" uncompresses to "AABABABAABABAB", and "A(2,B)" uncompresses to "ABB". The latter example is uncompressed as follows:

  1. "A(2,B)" is in form 2, where S = "A" and T= "(2,B)". S is in form 1 so it's already uncompressed. Next, we uncompress T.
  2. "(2,B)" is in form 3, where X = 2 and S = "B". S is in form 1 so it's already uncompressed. We concatenate 2 copies of it to get "BB".
  3. We concatenate S and T from step 1 to get "ABB".

A maximal continuous sequence of the same letter in a word is called a block. For example, "AABAAABBBAA" contains 5 blocks: AA, B, AAA, BBB, and AA.

You are given a compressed word. Return the number of blocks in the uncompressed form of the word.

Definition

Class:
BlockCounter
Method:
countBlocks
Parameters:
String
Returns:
long
Method signature:
long countBlocks(String word)
(be sure your method is public)

Constraints

  • word will contain between 1 and 50 characters, inclusive.
  • word will contain only parenthesis '(', ')', digits '1'-'9', letters 'A' and 'B' and commas ','.
  • word will be formatted as described in the problems statement.

Examples

  1. "(2,A(3,AB))"
    Returns: 12
    The example from the problem statement.
  2. "A(1,A)A(5,AAA)"
    Returns: 1
    In this case the word uncompresses to a string of 18 'A'-s.
  3. "ABA(2,ABA)(3,ABA)"
    Returns: 13
  4. "(3,(2,(1,AB)))B"
    Returns: 12
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