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JBaack's solution

to Word Search in the Lua Track

Published at Dec 13 2019 · 0 comments
Instructions
Test suite
Solution

In word search puzzles you get a square of letters and have to find specific words in them.

For example:

jefblpepre
camdcimgtc
oivokprjsm
pbwasqroua
rixilelhrs
wolcqlirpc
screeaumgr
alxhpburyi
jalaycalmp
clojurermt

There are several programming languages hidden in the above square.

Words can be hidden in all kinds of directions: left-to-right, right-to-left, vertical and diagonal.

Given a puzzle and a list of words return the location of the first and last letter of each word.

Running the tests

To run the tests, run the command busted from within the exercise directory.

Further information

For more detailed information about the Lua track, including how to get help if you're having trouble, please visit the exercism.io Lua language page.

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

word-search_spec.lua

local WordSearch = require('word-search')

describe('word-search', function()
  local puzzle = {
    'jefblpepre',
    'camdcimgtc',
    'oivokprjsm',
    'pbwasqroua',
    'rixilelhrs',
    'wolcqlirpc',
    'screeaumgr',
    'alxhpburyi',
    'jalaycalmp',
    'clojurermt',
  }

  it('should find horizontal words written left-to-right', function()
    local first, last = WordSearch(puzzle).find('clojure')
    assert.same({ 1, 10 }, first)
    assert.same({ 7, 10 }, last)
  end)

  it('should find horizontal words written right-to-left', function()
    local first, last = WordSearch(puzzle).find('elixir')
    assert.same({ 6, 5 }, first)
    assert.same({ 1, 5 }, last)
  end)

  it('should find vertical words written top-to-bottom', function()
    local first, last = WordSearch(puzzle).find('ecmascript')
    assert.same({ 10, 1 }, first)
    assert.same({ 10, 10 }, last)
  end)

  it('should find vertical words written bottom-to-top', function()
    local first, last = WordSearch(puzzle).find('rust')
    assert.same({ 9, 5 }, first)
    assert.same({ 9, 2 }, last)
  end)

  it('should find diagonal words written top-left-to-bottom-right', function()
    local first, last = WordSearch(puzzle).find('java')
    assert.same({ 1, 1 }, first)
    assert.same({ 4, 4 }, last)
  end)

  it('should find diagonal upper written bottom-right-to-top-left', function()
    local first, last = WordSearch(puzzle).find('lua')
    assert.same({ 8, 9 }, first)
    assert.same({ 6, 7 }, last)
  end)

  it('should find diagonal upper written bottom-left-to-top-right', function()
    local first, last = WordSearch(puzzle).find('lisp')
    assert.same({ 3, 6 }, first)
    assert.same({ 6, 3 }, last)
  end)

  it('should find diagonal upper written top-right-to-bottom-left', function()
    local first, last = WordSearch(puzzle).find('ruby')
    assert.same({ 8, 6 }, first)
    assert.same({ 5, 9 }, last)
  end)

  it('should not find words that are not in the puzzle', function()
    local first, last = WordSearch(puzzle).find('haskell')
    assert.same(nil, first)
    assert.same(nil, last)
  end)

  it('should be able to search differently-sized puzzles', function()
    local puzzle = {
      'qwertyuiopz',
      'luamsicrexe',
      'abcdefghijk'
    }
    local first, last = WordSearch(puzzle).find('exercism')
    assert.same({ 11, 2 }, first)
    assert.same({ 4, 2 }, last)
  end)
end)
return function(puzzle)

   local first = {nil, nil}
   local last = {nil, nil}

   function col_check(word)
      local drow = string.reverse(word)
      local column = ""
      for col = 1, #puzzle[1] do
         column = ""
         for row = 1, #puzzle do
            column = column .. string.sub(puzzle[row], col, col)
         end
         first[2], last[2] = string.find(column, word)
         if(first[2] == nil) then
            last[2], first[2] = string.find(column, drow)
         end
         if(first[2] ~= nil) then
            first[1] = col
            last[1] = col
            return first[1]
         end
      end
      return first[1]
   end

   function row_check(word)
      local drow = string.reverse(word)
      for row = 1, #puzzle do
         first[1], last[1] = string.find(puzzle[row], word)
         if(first[1] == nil) then
            last[1], first[1] = string.find(puzzle[row], drow)
         end
         if(first[1] ~= nil) then
            first[2] = row
            last[2] = row
            break
         end
      end
      return first[1]
   end

   function diag_forward(word)
      local drow = string.reverse(word)
      local diag_word = ""
      local offset = 0
      for col_pos = 1, #puzzle[1] - 1 do
            for diag = col_pos, #puzzle[1] do
               diag_word = diag_word .. string.sub(puzzle[diag - offset], diag, diag)
            end
            first[2], last[2] = diag_word:find(word)
            if(first[2] == nil) then
               last[2], first[2] = diag_word:find(drow)
            end
            if(first[2] ~= nil) then
               first[1] = first[2]
               last[1] = last[2]
               return first[1]
            end
         offset = col_pos
         diag_word = ""
      end
      offset = 0
      diag_word = ""
      for row_pos = 1, #puzzle[1] - 1 do
            for diag = row_pos, #puzzle do
               diag_word = diag_word .. string.sub(puzzle[diag], diag - offset, diag - offset)
            end
            first[1], last[1] = diag_word:find(word)
            if(first[1] == nil) then
               last[1], first[1] = diag_word:find(drow)
            end
            if(first[1] ~= nil) then
               first[2] = first[1] + offset
               last[2] = last[1] + offset
               return first[1]
            end
         offset = row_pos
         diag_word = ""
      end
      return first[1]
   end

      function diag_reverse(word)
         local drow = string.reverse(word)
         local diag_word = ""
         local row = 1
         for col_pos = #puzzle[1], 2, -1 do
               for diag = col_pos, 1, -1 do
                  diag_word = diag_word .. string.sub(puzzle[row], diag, diag)
                  row = row + 1
               end
               first[2], last[2] = diag_word:find(word)
               if(first[2] == nil) then
                  last[2], first[2] = diag_word:find(drow)
               end
               if(first[2] ~= nil) then
                  first[1] = col_pos + 1 - first[2]
                  last[1] = col_pos + 1 - last[2]
                  return first[1]
               end
            row = 1
            diag_word = ""
         end
         column = #puzzle[1]
         diag_word = ""
         for row_pos = 2, #puzzle - 1 do
               for diag = row_pos, #puzzle do
                  diag_word = diag_word .. string.sub(puzzle[diag], column, column)
                  column = column - 1
               end
               first[1], last[1] = diag_word:find(word)
               if(first[1] == nil) then
                  last[1], first[1] = diag_word:find(drow)
               end
               if(first[1] ~= nil) then
                  first[1] = #puzzle + 1 - first[1]
                  first[2] = row_pos + #puzzle[row_pos] - first[1]
                  last[1] = #puzzle + 1 - last[1]
                  last[2] = row_pos + #puzzle[row_pos] - last[1]
                  return first[1]
               end
            column = #puzzle[1]
            diag_word = ""
         end
         return first[1]
      end

   return{
      find = function(word)
         if(nil ~= row_check(word)) then
            return first, last
         elseif(nil ~= col_check(word)) then
            return first, last
         elseif(nil ~= diag_forward(word)) then
            return first, last
         elseif(nil ~= diag_reverse(word)) then
            return first, last
         end

         return nil
      end
   }
end

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