Cryptoarithmetic Solver

Cryptoarithmetic Solver .markdown

Cryptoarithmetic Solver

A Pen by Sher Minn Chong on CodePen.

License.

index.html

article 
  header
    .container 
      h1 Cryptoarithmetic Solver
      
  section
    .container 
      h2 Puzzle
      form#puzzle-form
          .form-group
            input#puzzle.form-control(type="text", placeholder="Puzzle", value="ODD+ODD==EVEN")
          .form-group
            input.pull-left.btn.btn-primary.btn-solve(type="submit") 
          
    section.solution
      .container
        h2 Solution
        .well
          ul#solutions
          

script.js

$(function(){
  var $solutionsContainer = $('.solution').hide();
  var $btn = $('.btn-solve');
  var $solutions = $('#solutions').html("");
  $('#puzzle-form').submit(function(event){
    event.preventDefault();    
    var puzzle = $('#puzzle', event.target).val();
    $btn.val('Solving...');
    
    // solve
    var solutions = solve(puzzle); 
    $btn.val("Submit");
    
    // display results
    $solutionsContainer.show(); 
    $solutions.html("");
    for(var s of solutions){
      $solutions.append('<li>' + s + '</li>');
    }
    
    if(solutions.length == 0){
      $solutions.html('No solution')
    }
  });
});

function solve(puzzle){
  var chars = uniqueChars(puzzle).join("");
  var combinations = Combinatorics.permutation([0,1,2,3,4,5,6,7,8,9], chars.length);
  var results = [];
  var compiled = compile(puzzle);
  if(!compiled){
    return [];
  }
  while(c = combinations.next()){
    if(compiled.apply(null, c)){
      var filled = replace(puzzle, chars, c.join(""));
      results.push(filled);
    }    
  }
  console.log(results);
  return results;
}

// returns unique alphabets in text
function uniqueChars(text){
  var set = new Set(text.match(/[A-Z]/g)).values();
  var arr = [];
  for (s of set){ arr.push(s)}
  return arr;
}

// compile puzzle
function compile(puzzle){
  var params = uniqueChars(puzzle).join(",");

  // get leading digits
  var leadingPattern = /\b([A-Z])[A-Z]/g;
  var leadingDigits = [];
  while((results = leadingPattern.exec(puzzle))){
    leadingDigits.push(results[1]);
  }
  var leadingDigitsStr = "[" + leadingDigits.join(",") + "]"
  
  // compile expression
  var tokens = puzzle.split(/([A-Z]+)/g);
  var exp = tokens.map(compileWord).join(" ");

  // put together function
  var func = "(function f(" + params 
      + "){ if(" + leadingDigitsStr + ".indexOf(0) == -1){ " 
      + "return " + exp + "} "
      + "else {return false}})";

  var fn;
  
  // catch eval errors
  try{
    fn = eval(func);
  }
  catch(err){
    alert(err.message);
    return false;
  }
  
  return fn;
}

function compileWord(word){
  if(/[A-Z]/g.test(word)){
    var digits = []; 
    for(var i = 0; i < word.length; i++){
      var zeroes = Math.pow(10, word.length - 1 - i)
      var digit = word[i] + '*' + zeroes;
      digits.push(digit);
    }
    return "(" + digits.join('+') + ")";
  }
  else{
    return word;
  } 
}

// replaces chars in intab with chars in outtab
function replace(text, intab, outtab){
  intab = intab.split(""); outtab = outtab.split(""); 
  var table = {};
  for(var i in intab){
    table[intab[i]] = outtab[i];
  }
  
  var translated = text.split("");
  translated.map(function(curr, index, arr){
    if(curr in table) arr[index] = table[curr];
  });

  return translated.join("");
}

function test(){
  console.log(replace('ODD+ODD==EVEN', 'ODEVN', '12345'));
  var f = compile('ODD+ODD==EVEN');
  console.log(f(0, 1, 2, 3, 4));
  var g = compile('MEE+YOU==OKAY');
  console.log(g(0, 1, 2, 3, 4));
}

scripts

<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script src="https://rawgit.com/dankogai/js-combinatorics/master/combinatorics.js"></script>

style.css

$space: 20px
header, section
  margin-bottom: $space

styles

<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css" rel="stylesheet" />