Find a 9 letter string of characters that contains only letters from [acdegilmnoprstuw] such that the hash(the_string) is 910897038977002; If hash is defined with the given pseudo-code

instruction.md

Find a 9 letter string of characters that contains only letters from

acdegilmnoprstuw

such that the hash(the_string) is

910897038977002

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
}

For example, if we were trying to find the 7 letter string where hash(the_string) was 680131659347, the answer would be leepadg.

main.js

// Given character set
var set  = 'acdegilmnoprstuw';

// Hasging algorithm constants
var CONST_HASH = 7;
var CONST_MULT = 37;

/**
 * Hashing algorithm
 * @return 	{int}
 */
var hash = function(string) {
	var _hash = CONST_HASH;

	for(var i = 0; i < string.length; i++) {
		_hash = (_hash * CONST_MULT + set.indexOf(string[i]));
	}

	return _hash;
}

/**
 * Decodes the provided hashing algorithm
 * @return 	{str}
 */
var decode = function(_hash) {
	var
		decoded = '',
		// The position of the portion
		// of the decoded hash (letter) in the set
		positionsInSet = [],
		i;

	for(i = 0; _hash > CONST_MULT; i++) {
		// With a modulus, we are able to extract
		// the exact decoded (letter in the set).
		positionsInSet[i] = Math.floor(_hash % CONST_MULT);

		// Divide back to go past back the multiplied value
		// (constant value of 37)
		_hash /= 37;
	}

	// Translates the value of each index
	// to its respective letter in the set.
	// We start from the last position
	// for we are decoding it with a backwards logic.
	for(i = (positionsInSet.length - 1); i >= 0; i--) {
		// Concatenate each letter
		decoded += set[ positionsInSet[i] ];
	}

	return decoded;
}