# Suggestions for Shorter Approach

Tell us what’s happening:
Describe your issue in detail here.
My code is running perfectly.But can anyone suggest how can I shorter this code as its too lengthy approach.

``````  **Your code so far**
``````
``````
function smallestCommons(arr) {
var small=Math.min(...arr);
var big=Math.max(...arr);
var array=[];
var i=0;
var j=0;
//////Create the array of number range
for(i=small;i<=big;++i){
array.push(i);
}
////Create array of prime numbers less than bigger number
var array_prime=[2];
for(i=3;i<=big;++i){
var value=i;
//console.log(value);
var flag=-1;
for(j=2;j<value;++j){
if(value%j==0){
flag=1;
break;
}
}
if(flag==-1){
array_prime.push(value);
}
}
console.log(array_prime);

//Divide whole array by each element of prime number array
var arr_new=[];
for(i=0;i<array_prime.length;++i){
var count=0;
var num=array_prime[i];
for(j=0;j<array.length;++j){
if(array[j]>=num){
if(array[j]%num==0){
count=1;
array[j]=array[j]/num;
}
}
//console.log(array);
}
if(count==1){
arr_new.push(num)};
}
console.log("Original array=",array);

var new_array=[];
for(i=0;i<array.length;++i){
if(array[i]!==1){
new_array.push(array[i]);
}
}
new_array=new_array.sort();
for(i=0;i<new_array.length;++i){
var ans=new_array[i];
if(array_prime.includes(ans)){
arr_new.push(ans);
for(j=0;j<new_array.length;++j){
if(new_array[j]>=ans && new_array[j]%ans==0){
new_array[j]=new_array[j]/ans;
}
}
}
}
console.log(arr_new);
console.log(new_array);
var product=1;
for(var i=0;i<arr_new.length;++i){
product*=arr_new[i];
console.log(product);
}
console.log(product);
return product;
}

smallestCommons([23,18]);
``````
``````  **Your browser information:**
``````

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.77 Safari/537.36`

Challenge: Smallest Common Multiple

I delete all you comments so any comment you see I wrote:

``````function smallestCommons(arr) {
var small=Math.min(...arr);
var big=Math.max(...arr);
//you can simply do this:
//var array = [Math.min(...arr), Math.max(...arr)]
var array=[];

//You don't need to ever make i or j outside
//the context of a for loop
//this would be different if you were a
//while loop
var i=0;
var j=0;

for(i=small;i<=big;++i){
array.push(i);
}

//This is an improper naming convention for JS
//it should be arrayPrime
var array_prime=[2];
for(i=3;i<=big;++i){
//you don't need value you already have i
var value=i;

var flag=-1;
for(j=2;j<value;++j){
if(value%j==0){
flag=1;
break;
}
}
//this if could be inside the above loop so you
//wouldn’t need flag
if(flag==-1){
array_prime.push(value);
}
}

//Divide whole array by each element of prime number array
var arr_new=[];
for(i=0;i<array_prime.length;++i){
var count=0;
var num=array_prime[i];
for(j=0;j<array.length;++j){

//you don't need to ifs
//instead use the since they both must be true
//us the && operator between them
//in the same statement
if(array[j]>=num){
if(array[j]%num==0){
count=1;
array[j]=array[j]/num;
}
}
}
if(count==1){
arr_new.push(num)};
}

var new_array=[];
for(i=0;i<array.length;++i){
if(array[i]!==1){
new_array.push(array[i]);
}
}
//sort is a destructive method so
//you can simply call the method
new_array=new_array.sort();
for(i=0;i<new_array.length;++i){
var ans=new_array[i];
if(array_prime.includes(ans)){
arr_new.push(ans);
for(j=0;j<new_array.length;++j){
if(new_array[j]>=ans && new_array[j]%ans==0){
new_array[j]=new_array[j]/ans;
}
}
}
}

var product=1;
for(var i=0;i<arr_new.length;++i){
product*=arr_new[i];
console.log(product);
}

return product;
}

smallestCommons([23,18]);
``````

I did not read the entirety of you code, but the main two things I see making it longer are:

You make a lot of variables that don’t need to exist.

That vast majority of extra code is purely due to implementation, and I would recommend that you research effective ways of finding primes.

1 Like

Hi @riti0301 !

I added spoiler tags around your code since it is a working solution and we don’t want to spoil it for those who have not worked on this challenge.

1 Like
``````function smallestCommons(arr) {

//populate the array of numbers
let min=Math.min(...arr)
let max=Math.max(...arr)
let fullArr=[]
for (let i=min; i<=max; i++){
fullArr.push(i)
}

//test if a number is common multiple for all items
function compare(num){
return fullArr.every(n=>num%n==0)
}

// set from where to start comparing numbers...
// (largest number * second largest)
let multiple=max*(max-1)

while(!compare(multiple)){
// go thru multiples of the largest number in the list, ...
// until it finds one that is valid for all other numbers in the list
multiple+=max
}

// return the smallest number which is  evenly divisible by all
return multiple;
}
``````

Hello this is a solution i made and added some comments so you can follow the code. It should be pretty efficient, altho one could improve it even more

1 Like

If you want a much shorter solution, try using Euclidean algorithm.

1 Like

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