Top Secret for now ;)

trellises.js

//	Author: Jaime Agudo <jaime.agudo.lopez@gmail.com>
//
//	Github: https://github.com/jaimeagudo/
//
//	License: MIT


'use strict';

/*

 Write JavaScript (or CoffeeScript) code to find a 9 letter string of characters that contains only letters from

 acdegilmnoprstuw

 such that the hash(the_string) is

 956446786872726

 if hash is defined by the following pseudo-code:

 Int64 hash (String s) {
 Int64 h = 7
 String letters = "acdegilmnoprstuw"
 for(Int32 i = 0; i < s.length; i++) {
 h = (h * 37 + letters.indexOf(s[i]))
 }
 return h
 }p

 //for  680131659347, the answer would be "leepadg"

*/


var hash = function(s){
    var h = 7;
    var legalLetters = "acdegilmnoprstuw";
    var i;

    if(s && s.length){
	for(i = 0; i < s.length; i++) {
            h = (h * 37 + legalLetters.indexOf(s[i]));
        }
    }
    return h;
};

var stringToNumArray =function(s){
    var legalLetters = "acdegilmnoprstuw";
    var i, a=[];

    for(i = 0; i < s.length; i++)
        a.push(legalLetters.indexOf(s[i]));
    return a;
};


var numArrayToString =function(a){
    var legalLetters = "acdegilmnoprstuw";
    var i, s=[];

    for(i = 0; i < a.length; i++)
        s.push(legalLetters[a[i]]);

    return s.join('');
};

var hashNumbers = function(a){
    var h = 7;
    var i;

    if(a && a.length)
	for(i = 0; i < a.length; i++)
            h = (h * 37 + a[i]);

    return h;
};


//Just to test a correct translation
var hash2=function(s){
    return hashNumbers(stringToNumArray(s));
};

var reverseHash=function(n){

    var maxLength= "acdegilmnoprstuw".length;
    var i;

    var a=[];
    var h=n;

    while(h != 7){
        for(i=0; i < maxLength; i++){
            if((h - i) % 37 === 0){
                a.push(i);
                //just in case floating point calculations do weird things
                h=Math.floor((h - i) / 37);
                break;
            }
        }
    }
    return numArrayToString(a.reverse());

};


numArrayToString(stringToNumArray("leepadg"));

//console.log(hash("leepadg"));
//console.log(hash2("leepadg"));
var l=680131659347;
var leepadg="leepadg";
reverseHash(l);//leepadg
var x=956446786872726
var the_string=reverseHash(x); //trellises
console.log(the_string);