Game of life (1) P26100


Statement
 

pdf   zip

html

The English mathematician John Conway invented in 1970 the following game: Imagine a matrix with n rows and m columns. We consider neighbor positions to a given position the (at most, eight) adjacent positions, either horizontally, vertically or diagonally. Every moment, each position is either empty or it contains a bacterium. The rules are:

  • An empty position at time t will contain a bacterium at time t + 1 if and only if at time t it had exactly three neighbor bacteria.
  • An occupied position at time t will contain a bacterium at time t + 1 if and only if at time t it had two or three neighbor bacteria.

Write a program that, for every given matrix, prints it at the next moment of time.

Input

Input consists of several cases. Every case begins with n and m (both strictly positive), followed by n lines, each one with m characters: ‘B’ if the position has a bacterium, and ‘.’ if the position is empty. A special case with n = m = 0 marks the end of the input.

Output

For each case, print the matrix corresponding to the next moment of time using the same format of the input (do not print n and m). Separate matrices with an empty line.

Public test cases
  • Input

    2 3
    B.B
    .B.
    
    2 2
    BB
    BB
    
    0 0
    

    Output

    .B.
    .B.
    
    BB
    BB
    
  • Information
    Author
    Salvador Roura
    Language
    English
    Translator
    Carlos Molina
    Original language
    Catalan
    Other languages
    Catalan
    Official solutions
    C++ Java Python
    User solutions
    C++