word_search

word_search.rb

def next_moves(current,paths,board)
  [[-1,0],[1,0],[0,-1],[0,1]].map{|walk| [(current[0]+walk[0]),(current[1]+walk[1])]}.select do |next_pos|
    !(paths.include? next_pos) and next_pos.all?{|pos| pos >=0 } and next_pos[0] < board.size and next_pos[1] <= board[next_pos[0]].size
  end
end

def next_moves_match(next_pos,next_char,board)
  board[next_pos[0]][next_pos[1]] == next_char
end

def walk_through current,path,chars,board
  return true if chars.empty?
  next_moves(current,path,board).each do |next_pos|
    res = next_moves_match(next_pos,chars.first,board) ?  walk_through(next_pos,path+[current],chars[1..-1],board) : false
    return true if res
  end
  false
end

def find_word(board,word)
  board.each_with_index do |row,index_r|
    row.each_with_index do |v,index_l|
      if v == word.chars.first
        return true if walk_through([index_r,index_l],[],word.chars[1..-1],board)
      end
    end
  end
  false
end

def find_words(board,words)
  words.select{|word| find_word(board,word) }
end