Run results for: codewars test alex

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36

Browser: Chrome 63

Operating system: Mac OS X 10.13.2

Device Platform: Other

Date tested: 2024 years ago

Test name	Executions per second
my solution	292.5 Ops/sec
best solution	5948.6 Ops/sec

Script Preparation code:

function bestListPosition(word) {
    var indexer = {}; // D:3 B:1 A:0 C:2
    var counts = []; // 2 1 1 1

    var lettersCount = 0;
    word.split("").sort().forEach(function(x){
        if ( indexer[x] == undefined ) {
            indexer[x] = lettersCount;
            counts[lettersCount] = 0;
            lettersCount ++;
        }
    });

    var term = 1;
    var sum = term;
    word.split("").reverse().forEach(function(x, i){
        var step = i + 1, idx = indexer[x];
        counts[idx] ++;
        term /= counts[idx];
        for (var j = 0; j < idx; ++j) 
            if (counts[j] != 0) 
                sum += term * counts[j];
        term *= step;
    });
    return sum;
}

function myListPosition(word) {
  console.log(word);
  var array = word.split('');
  var sorted = array.slice().sort();
  return word_helper(array, sorted);
}

function word_helper(array, sorted){
  if (array.length === 0) return 1;
  
  var first = array[0];
  
  if (first === sorted[0]){
    return word_helper(array.slice(1), sorted.slice(1));
  }
  
  var done=[];
  var num = 0;
  for (let i = 0; sorted[i] !== first; i++){
    if (done.length && done[done.length - 1] === sorted[i])
      continue;
    done.push(sorted[i]);
    
    num += permutations(remove(array, sorted[i]), remove(sorted, sorted[i])); 
  }
  
  return num + word_helper(array.slice(1), remove(sorted, first));
}

function remove(array, element){
  return array.slice(0, array.indexOf(element))
    .concat(array.slice(array.indexOf(element) + 1));
}

function permutations(array, sorted){
  var dups = [];
  current = 0;
  for (let i = 1; i < sorted.length; i++){
    if (sorted[i] === sorted[i-1]){
      current += current ? 1 : 2;
    } else if (current){
      dups.push(current);
      current = 0;
    }
  }
  if (current) dups.push(current);
  return factorial(array.length) / dups.reduce((p,c) => p * factorial(c), 1);
}

function factorial(n){
  var ret = 1;
  for (; n > 0; n--){
    ret *= n;
  }
  return ret;
}

test_words='thing|qergqergqebqergqerghwervqeg|wergqeruihoiuehfoiuh|gelrjflibqhf|greigubwreiugbqerg|qqergwrgqergfwrrth|bwnfofbbwoobgbjhwfhbbbhwofbbwofbgbw'.split('');

Tests:

my solution
for(word of test_words){ myListPosition(word); }
best solution
for (word of test_words){ bestListPosition(word); }

Run results for: codewars test alex

my solution

best solution