Minimum number of digit changes to get two arrays to have the same value

Question

I am pretty new to coding and I'm trying my best, but after hours and hours of research i still cant figure this out. I'm trying to make these two separate arrays the same with the minimum number of moves. I can only ++ or -- one number at a time.

This is the challenge:

No reordering of the digits is allowed For example, consider two arrays: Andrea's [123, 543] and Maria's [321, 279]. For the first digit, Andrea can increment the 1 twice to achieve 3. The 2's are equal already. Finally, she decrements her 3 twice to equal 1. It took 4 moves to reach her goal. For the second integer, she decrements 5 three times, increments 4 three times and 3 six times. It took 12 moves to convert the second array element. In total, it took 16 moves to convert both values comprising the complete array.

let a = [1234, 4321]
let m = [2345, 3214]

function minimumMoves(a, m) {
    // Write your code here
    let numMoves = 0;
    let num1 = '' ;
    let num2 = '' ;
    let digit1 = '';
    let digit2= '';
    for (let i = 0; i < a.length; i++)
    {
        num1 = a[i]; 
        while (num1 != 0) {
            digit1 = num1 % 10; 
            digit2 = num2 % 10; 
            num1 = Math.trunc(num1 / 10); 
            num2 = Math.trunc(num2 / 10);
            numMoves = numMoves + Math.abs(digit1 - digit2);

        }
    }
    return numMoves
}

It's not clear to me what you're trying to do. please add a better description and examples of input and expected output, thanks! — Nir Alfasi, Mar 15 '19 at 19:39

Zargold · Answer 1 · 2019-03-15T20:07:27.980

In my opinion you should make a function that effectively takes a single digit and while it is greater than the other number aka needs to be decremented it does that:

const incrementWhileNeeded = (target, currentValue) =>
  Math.abs(target - currentValue)

Then, you need split the numbers into their digits (you can do this the mathematical way using % like it looks like you've done, but just for simplicity something like: String(num1).split('').map(Number) will take 451 and change it to [4, 5, 1].

Then, your next step is to map that function (incrementWhileNeeded) to each individual digit: just focus on the first number (and then apply forEach or .map to apply that function to all of them.

So that will look something like: firstNumberArray.map(incrementWhileNeeded)

Which will respond with as you explained [1, 0, 2].

Then .reduce() this so that you can get the sum of the counts. So this will reduce using [1,0,2].reduce((accumulator, current) => accumulator + current) to 3.

So for the full functionality:

const incrementWhileNeeded = (target, currentValue) =>
      Math.abs(target - currentValue)

const calculateMinimumMoves = (fullNumber, targetNumber) => {
      const numArray = String(fullNumber).split('').map(Number)
      const targetArray = String(targetNumber).split('').map(Number)
      const diffArray = numArray.map((currentElement, targetArray[index]) => incrementWhileNeeded(currentElement, targetArray[index])
      return diffArray.reduce((accumulator, current) => accumulator + current, 0)
}

const minimumMoves = (array1, array2) =>
      array1.reduce((accumulator, current, index) =>
            accumulator + calculateMinimumMoves(current, array2[index]),
            0)

Nina Scholz · Answer 2 · 2019-03-15T19:56:49.377

1

For getting only the count for changina a string of digits to another, you could add the absolute delta of the digits at a place.

function count(a, b) {
    return Array.from(a).reduce((s, v, i) => s + Math.abs(v - b[i]), 0);
}

console.log(count('123', '321'));

edited Mar 15 '19 at 19:56

answered Mar 15 '19 at 19:43

Nina Scholz

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score 0 · Accepted Answer · answered Mar 15 '19 at 20:57

Check this code out:

a = [1234, 4321]
b = [2345, 3214]

function minimumMoves(a, m) {
    let numMoves1 = 0, numMoves2 = 0;
    let num1 = '', num2 = '';
    let digit1 = '', digit2 = '';
    //Forward
    for (let i = 0 ; i < a.length ; i++)
    {
        num1 = a[i];
        num2 = m[i];
        for (let j = 0 ; j < a.length ; j++)
        {
            digit1 = num1 % 10;
            digit2 = num2 % 10;
            numMoves1 += Math.abs(digit1-digit2);
            num1 = (num1 - digit1) / 10;
            num2 = (num2 - digit2) / 10;
        }
    }
    //Backward
    for (let i = 0 ; i < a.length ; i++)
    {
        num1 = m[i];
        num2 = a[i];
        for (let j = 0 ; j < a.length ; j++)
        {
            digit1 = num1 % 10;
            digit2 = num2 % 10;
            numMoves2 += Math.abs(digit1-digit2);
            num1 = (num1 - digit1) / 10;
            num2 = (num2 - digit2) / 10;
        }
    }
    if (numMoves1>numMoves2)
    {
        //Answer is numMoves1
    } else if (numMoves1<numMoves2)
    {
        //Answer is numMoves2
    } else {
        //Answer is any one, i.e, either numMoves1 or numMoves2
    }
}

If you need quick verification for this code, navigate Here.

And then paste this code:

/******************************************************************************

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public class Main
{
    public static void main(String[] args) {
        Integer[] a = {1234, 4321};
        Integer[] m = {2345, 3214};
        Integer numMoves1 = 0, numMoves2 = 0;
        Integer num1 = 0, num2 = 0;
        Integer digit1 = 0, digit2 = 0;
        //Forward
        for (Integer i = 0 ; i < a.length ; i++)
        {
            num1 = a[i];
            num2 = m[i];
            for (Integer j = 0 ; j < a.length ; j++)
            {
                digit1 = num1 % 10;
                digit2 = num2 % 10;
                numMoves1 += Math.abs(digit1-digit2);
                num1 = (num1 - digit1) / 10;
                num2 = (num2 - digit2) / 10;
            }
        }
        //Backward
        for (Integer i = 0 ; i < a.length ; i++)
        {
            num1 = m[i];
            num2 = a[i];
            for (Integer j = 0 ; j < a.length ; j++)
            {
                digit1 = num1 % 10;
                digit2 = num2 % 10;
                numMoves2 += Math.abs(digit1-digit2);
                num1 = (num1 - digit1) / 10;
                num2 = (num2 - digit2) / 10;
            }
        }
        if (numMoves1>numMoves2)
        {
            //Answer is numMoves1
        } else if (numMoves1<numMoves2)
        {
            //Answer is numMoves2
        } else
        {
            //Answer is any one, i.e, either numMoves1 or numMoves2
        }
        System.out.println(numMoves1 + " & " + numMoves2);
    }
}

I hope this algorithm helps ;)

You can customize the input in the array initialization statement. — Saumitra Topinkatti, Mar 15 '19 at 21:02

score 0 · Answer 4 · answered Jan 24 '21 at 05:59

//This code works....
// Check this out ....
public class Main
{
    public static void main(String[] args) {
        Integer[] a = {1234, 4321};
        Integer[] m = {2345, 3214};
        Integer numMoves1 = 0;
        Integer num1 = 0, num2 = 0;
        Integer digit1 = 0, digit2 = 0;
        //Forward
        for (Integer i = 0 ; i < a.length ; i++)
        {
            num1 = a[i];
            num2 = m[i];
           while(num1>0)
            {
                digit1 = num1 % 10;
                digit2 = num2 % 10;
                numMoves1 += Math.abs(digit1-digit2);
                num1 = (num1 - digit1) / 10;
                num2 = (num2 - digit2) / 10;
            }
        }
        System.out.println(numMoves1);
    }
}

Please don't post only code as an answer, but also provide an explanation of what your code does and how it solves the problem of the question. Answers with an explanation are usually more helpful and of better quality, and are more likely to attract upvotes — Ran Marciano, Jan 24 '21 at 06:01

score 0 · Answer 5 · answered Mar 25 '21 at 09:58

Here is the solution for finding the minimum moves to match each of the elements of the two different array.

let a = [1234, 4321]
let m = [2345, 3214]

function minimumMoves(a, m) {
    // Write your code here
    let numMoves = 0;
    let num1 = '' ;
    let num2 = '' ;
    let digit1 = '';
    let digit2= '';
    for (let i = 0; i < a.length; i++)
    {      
        num1 = a[i]; 
        num2 = m[i];      
        while (num1 != 0) {
          
            digit1 = num1 % 10; 
            digit2 = num2 % 10; 
            num1 = Math.trunc(num1 / 10); 
            num2 = Math.trunc(num2 / 10);
            numMoves = numMoves + Math.abs(digit1 - digit2);

        }
    }
    return numMoves;
}

console.log(minimumMoves(a, m));

Minimum number of digit changes to get two arrays to have the same value

5 Answers5