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# Nia11's solution

## to Word Search in the Lua Track

Published at Dec 06 2018 · 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()
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)``````
``````local lines
local first
local last
local directions={{0,-1},{-1,-1},{-1,0},{-1,1},{0,1},{1,1},{1,0},{1,-1}}

local function match(word,cord,direction)
local newrow = cord[1]+direction[1]
local newcol = cord[2]+direction[2]

if newrow<1 or newrow>#lines then return false end
local newline = lines[newrow]

if newcol<1 or newcol>#newline then return false end
local newchar = newline:sub(newcol,newcol)

if newchar==word then
last={newrow,newcol}
return true
elseif newchar==word:sub(1,1) then
return match(word:sub(2),{newrow,newcol},direction)
else
return false
end

end

local function reverse(tab)
--this is here to reverse the cooridinate values for output tables, that's the way the spec wnats it....
return {tab[2],tab[1]}
end

return function(puzzle)
return{
find = function(str)
lines=puzzle
local found=false
for i=1,#lines do
for c=1,#lines[i] do
if str:sub(1,1)==lines[i]:sub(c,c) then
first={i,c}
for k,v in pairs(directions) do
found = match(str:sub(2),first,v)
if found then return reverse(first),reverse(last) end
end
end
end
end
end
}
end``````

### What can you learn from this solution?

A huge amount can be learned from reading other peopleâ€™s code. This is why we wanted to give exercism users the option of making their solutions public.

Here are some questions to help you reflect on this solution and learn the most from it.

• What compromises have been made?