N-Asadnajafi

function binarySearch(Array,startIndex, endIndex, x){
  middleIndex= Math.floor((startIndex + endIndex)/2);
  if(startIndex > endIndex)
    return -1;
  if (x == Array[middleIndex])
    return middleIndex;
  else if (x < Array[middleIndex])
    return binarySearch(Array, startIndex, middleIndex -1, x);
  else
    return binarySearch(Array, middleIndex + 1, endIndex, x);

N-Asadnajafi

function isLucky(n) {
var sumLeft = 0;
var sumRight = 0;
  
digits= n.toString().split('');//to make an array of characters, at first change the numbers to string and then use split() method.
ArrayNum = digits.map(Number);//we have an array of strings and want to change the type to numbers so we use .map() method.
len = ArrayNum.length;
  
if(len % 2 !==0){
  return false;//check if the "n" has even number of digits or not.

N-Asadnajafi

function commonCharacterCount(s1, s2){
  var e=0;
  ArrayS1 = s1.split('');//This method changes the string to an array.
  ArrayS2 = s2.split('');
  for(var i=0; i<ArrayS1.length;i++){
    for(var j=0; j<ArrayS2.length; j++){
      if(ArrayS1[i]==ArrayS2[j]){
        e++;
        ArrayS1.splice(i,1);//This method removes the ith and jth elements which are equal
        ArrayS2.splice(j,1);