Micro Coding Challenges - with solutions

Mastering these coding challenges may not get you a job at google... but you'll be one step closer to...

Mastering these coding challenges may not get you a job at google... but you'll be one step closer to understanding coding and building your first JavaScript game at codeguppy.com

These coding challenges are intended for beginners, therefore the solutions are implemented using only simple / classical programming elements. Each solution is accompanied by an online link that helps you quickly run it in a code playground at codeguppy.com

Note: The online code is making use of the codeguppy specific function println() to print the results. This helper function has a similar syntax with console.log()

Coding challenge #1: Print numbers from 1 to 10

https://codeguppy.com/code.html?mrgCtLGA90Ozr0Otrs5Z

js for(var i = 1; i <= 10; i++) { console.log(i); }

Coding challenge #2: Print the odd numbers less than 100

https://codeguppy.com/code.html?eDLA5XPp3bPxP79H2jKT

js for(var i = 1; i <= 100; i += 2) { console.log(i); }

Coding challenge #3: Print the multiplication table with 7

https://codeguppy.com/code.html?fpnQzIhnGUUmCUZy1fyQ

js for(var i = 1; i <= 10; i++) { var row = "7 * " + i + " = " + 7 * i; console.log(row); }

Coding challenge #4: Print all the multiplication tables with numbers from 1 to 10

https://codeguppy.com/code.html?78aD4mWSCzoNEVxOQ8tI

```js for(var i = 1; i <= 10; i++) { printTable(i); console.log(""); }

function printTable(n) { for(var i = 1; i <= 10; i++) { var row = n + " * " + i + " = " + n * i; console.log(row); } } ```

Coding challenge #5: Calculate the sum of numbers from 1 to 10

https://codeguppy.com/code.html?Vy6u9kki2hXM4YjsbpuN

```js var sum = 0;

for(var i = 1; i <= 10; i++) { sum += i; }

console.log(sum); ```

Coding challenge #6: Calculate 10!

https://codeguppy.com/code.html?IIuJX4gnXOndNu0VrywA

```js var prod = 1;

for(var i = 1; i <= 10; i++) { prod *= i; }

console.log(prod); ```

Coding challenge #7: Calculate the sum of even numbers greater than 10 and less than 30

https://codeguppy.com/code.html?DcOffOyoIArmNZHVNM2u

```js var sum = 0;

for(var i = 11; i <= 30; i += 2) { sum += i; }

console.log(sum); ```

Coding challenge #8: Create a function that will convert from Celsius to Fahrenheit

https://codeguppy.com/code.html?oI5mWm6QIMRjY1m9XAmI

```js function celsiusToFahrenheit(n) { return n * 1.8 + 32; }

var r = celsiusToFahrenheit(20); console.log(r); ```

Coding challenge #9: Create a function that will convert from Fahrenheit to Celsius

https://codeguppy.com/code.html?mhnf8DpPRqqgsBgbJNpz

```js function fahrenheitToCelsius(n) { return (n - 32) / 1.8; }

var r = fahrenheitToCelsius(68); console.log(r); ```

Coding challenge #10: Calculate the sum of numbers in an array of numbers

https://codeguppy.com/code.html?TteeVr0aj33ZyCLR685L

```js function sumArray(ar) { var sum = 0;

for(var i = 0; i < ar.length; i++)
{
    sum += ar[i];
}

return sum;

}

var ar = [2, 3, -1, 5, 7, 9, 10, 15, 95]; var sum = sumArray(ar); console.log(sum); ```

Coding challenge #11: Calculate the average of the numbers in an array of numbers

https://codeguppy.com/code.html?7i9sje6FuJsI44cuncLh

```js function averageArray(ar) { var n = ar.length; var sum = 0;

for(var i = 0; i < n; i++)
{
    sum += ar[i];
}

return sum / n;

}

var ar = [1, 3, 9, 15, 90]; var avg = averageArray(ar);

console.log("Average: ", avg); ```

Coding challenge #12: Create a function that receives an array of numbers and returns an array containing only the positive numbers

Solution 1:

https://codeguppy.com/code.html?0eztj1v6g7iQLzst3Id3

```js function getPositives(ar) { var ar2 = [];

for(var i = 0; i < ar.length; i++)
{
    var el = ar[i];

    if (el >= 0)
    {
        ar2.push(el);
    }
}

return ar2;

}

var ar = [-5, 10, -3, 12, -9, 5, 90, 0, 1]; var ar2 = getPositives(ar);

console.log(ar2); ```

Coding challenge #12: Create a function that receives an array of numbers and returns an array containing only the positive numbers

Solution 2

https://codeguppy.com/code.html?KefrPtrvJeMpQyrB8V2D

```js function getPositives(ar) { var ar2 = [];

for(var el of ar)
{
    if (el >= 0)
    {
        ar2.push(el);
    }
}

return ar2;

}

var ar = [-5, 10, -3, 12, -9, 5, 90, 0, 1]; var ar2 = getPositives(ar);

console.log(ar2); ```

Coding challenge #12: Create a function that receives an array of numbers and returns an array containing only the positive numbers

Solution 3

https://codeguppy.com/code.html?qJBQubNA7z10n6pjYmB8

```js function getPositives(ar) { return ar.filter(el => el >= 0); }

var ar = [-5, 10, -3, 12, -9, 5, 90, 0, 1]; var ar2 = getPositives(ar); console.log(ar2); ```

Coding challenge #13: Find the maximum number in an array of numbers

https://codeguppy.com/code.html?THmQGgOMRUj6PSvEV8HD

```js function findMax(ar) { var max = ar[0];

for(var i = 0; i < ar.length; i++)
{
    if (ar[i] > max)
    {
        max = ar[i];
    }
}

return max;

}

var ar = [-5, 10, -3, 12, -9, 5, 90, 0, 1]; var max = findMax(ar); console.log("Max: ", max); ```

Coding challenge #14: Print the first 10 Fibonacci numbers without recursion

https://codeguppy.com/code.html?rKOfPxHbVwxNWI2d8orH

```js var f0 = 0; console.log(f0);

var f1 = 1; console.log(f1);

for(var i = 2; i < 10; i++) { var fi = f1 + f0; console.log(fi);

f0 = f1;
f1 = fi;

} ```

Coding challenge #15: Create a function that will find the nth Fibonacci number using recursion

https://codeguppy.com/code.html?IneuIg9O0rRV8V76omBk

```js function findFibonacci(n) { if (n == 0) return 0;

if (n == 1)
    return 1;

return findFibonacci(n - 1) + findFibonacci(n - 2);

}

var n = findFibonacci(10); console.log(n); ```

Coding challenge #16: Create a function that will return a Boolean specifying if a number is prime

https://codeguppy.com/code.html?fRYsPEc2vcZTbIU8MKku

```js function isPrime(n) { if (n < 2) return false;

if (n == 2)
    return true;

var maxDiv = Math.sqrt(n);

for(var i = 2; i <= maxDiv; i++)
{
    if (n % i == 0)
    {
        return false;
    }
}

return true;

}

console.log(2, " is prime? ", isPrime(2)); console.log(3, " is prime? ", isPrime(3)); console.log(4, " is prime? ", isPrime(4)); console.log(5, " is prime? ", isPrime(5)); console.log(9, " is prime? ", isPrime(9)); ```

Coding challenge #17: Calculate the sum of digits of a positive integer number

https://codeguppy.com/code.html?RHA714FYio8gWgmjWYPz

```js function sumDigits(n) { var s = n.toString(); var sum = 0;

for(var char of s)
{
    var digit = parseInt(char);
    sum += digit;
}

return sum;

}

var sum = sumDigits(1235231); console.log("Sum: ", sum); ```

Coding challenge #18: Print the first 100 prime numbers

https://codeguppy.com/code.html?gnMVeOZXN6VhLekyvui8

```js printPrimes(100);

// Function prints the first nPrimes numbers function printPrimes(nPrimes) { var n = 0; var i = 2;

while(n < nPrimes)
{
    if (isPrime(i))
    {
        console.log(n, " --> ", i);
        n++;
    }

    i++;
}

}

// Returns true if a number is prime function isPrime(n) { if (n < 2) return false;

if (n == 2)
    return true;

var maxDiv = Math.sqrt(n);

for(var i = 2; i <= maxDiv; i++)
{
    if (n % i == 0)
    {
        return false;
    }
}

return true;

} ```

Coding challenge #19: Create a function that will return in an array the first "nPrimes" prime numbers greater than a particular number "startAt"

https://codeguppy.com/code.html?mTi7EdKrviwIn4bfrmM7

```js console.log(getPrimes(10, 100));

function getPrimes(nPrimes, startAt) { var ar = [];

var i = startAt;

while(ar.length < nPrimes)
{
    if (isPrime(i))
    {
        ar.push(i);
    }

    i++;
}

return ar;

}

// Returns true if a number is prime function isPrime(n) { if (n < 2) return false;

if (n == 2)
    return true;

var maxDiv = Math.sqrt(n);

for(var i = 2; i <= maxDiv; i++)
{
    if (n % i == 0)
    {
        return false;
    }
}

return true;

} ```

Coding challenge #20: Rotate an array to the left 1 position

https://codeguppy.com/code.html?MRmfvuQdZpHn0k03hITn

```js var ar = [1, 2, 3]; rotateLeft(ar); console.log(ar);

function rotateLeft(ar) { var first = ar.shift(); ar.push(first); } ```

Coding challenge #21: Rotate an array to the right 1 position

https://codeguppy.com/code.html?fHfZqUmkAVUXKtRupmzZ

```js var ar = [1, 2, 3]; rotateRight(ar); console.log(ar);

function rotateRight(ar) { var last = ar.pop(); ar.unshift(last); } ```

Coding challenge #22: Reverse an array

https://codeguppy.com/code.html?GZddBqBVFlqYrsxi3Vbu

```js var ar = [1, 2, 3]; var ar2 = reverseArray(ar); console.log(ar2);

function reverseArray(ar) { var ar2 = [];

for(var i = ar.length - 1; i >= 0; i--)
{
    ar2.push(ar[i]);
}

return ar2;

} ```

Coding challenge #23: Reverse a string

https://codeguppy.com/code.html?pGpyBz0dWlsj7KR3WnFF

```js var s = reverseString("JavaScript"); console.log(s);

function reverseString(s) { var s2 = "";

for(var i = s.length - 1; i >= 0; i--)
{
    var char = s[i];
    s2 += char;
}

return s2;

} ```

## Coding challenge #24: Create a function that will merge two arrays and return the result as a new array

https://codeguppy.com/code.html?vcTkLxYTAbIflqdUKivc

```js var ar1 = [1, 2, 3]; var ar2 = [4, 5, 6];

var ar = mergeArrays(ar1, ar2); console.log(ar);

function mergeArrays(ar1, ar2) { var ar = [];

for(let el of ar1)
{
    ar.push(el);
}

for(let el of ar2)
{
    ar.push(el);
}

return ar;

} ```

Coding challenge #25: Create a function that will receive two arrays of numbers as arguments and return an array composed of all the numbers that are either in the first array or second array but not in both

https://codeguppy.com/code.html?Y9gRdgrl6PPt4QxVs7vf

```js var ar1 = [1, 2, 3, 10, 5, 3, 14]; var ar2 = [1, 4, 5, 6, 14];

var ar = mergeExclusive(ar1, ar2); console.log(ar);

function mergeExclusive(ar1, ar2) { var ar = [];

for(let el of ar1)
{
    if (!ar2.includes(el))
    {
        ar.push(el);
    }
}

for(let el of ar2)
{
    if (!ar1.includes(el))
    {
        ar.push(el);
    }
}

return ar;

} ```

Coding challenge #26: Create a function that will receive two arrays and will return an array with elements that are in the first array but not in the second

https://codeguppy.com/code.html?bUduoyY6FfwV5nQGdXzH

```js var ar1 = [1, 2, 3, 10, 5, 3, 14]; var ar2 = [-1, 4, 5, 6, 14];

var ar = mergeLeft(ar1, ar2); console.log(ar);

function mergeLeft(ar1, ar2) { var ar = [];

for(let el of ar1)
{
    if (!ar2.includes(el))
    {
        ar.push(el);
    }
}

return ar;

} ```

Coding challenge #27: Create a function that will receive an array of numbers as argument and will return a new array with distinct elements

Solution 1

https://codeguppy.com/code.html?OkbtP1ZksGHXwqk7Jh3i

```js var ar = getDistinctElements([1, 2, 3, 6, -1, 2, 9, 7, 10, -1, 100]); console.log(ar);

function getDistinctElements(ar) { var ar2 = [];

for(let i = 0; i < ar.length; i++)
{
    if (!isInArray(ar[i], ar2))
    {
        ar2.push(ar[i]);
    }
}

return ar2;

}

function isInArray(n, ar) { for(let i = 0; i < ar.length; i++) { if (ar[i] === n) return true; }

return false;

} ```

Coding challenge #27: Create a function that will receive an array of numbers as argument and will return a new array with distinct elements

Solution 2

https://codeguppy.com/code.html?NjGtyQdMP49QiaAkmwpU

```js var ar = getDistinctElements([1, 2, 3, 6, -1, 2, 9, 7, 10, -1, 100]); console.log(ar);

function getDistinctElements(ar) { var ar2 = [];

var lastIndex = ar.length - 1;

for(let i = 0; i <= lastIndex; i++)
{
    if (!isInArray(ar[i], ar, i + 1, lastIndex))
    {
        ar2.push(ar[i]);
    }
}

return ar2;

}

function isInArray(n, ar, fromIndex, toIndex) { for(var i = fromIndex; i <= toIndex; i++) { if (ar[i] === n) return true; }

return false;

} ```

Coding challenge #28: Calculate the sum of first 100 prime numbers

https://codeguppy.com/code.html?v0O9sBfnHbCi1StE2TxA

```js var n = 10; console.log("Sum of first ", n, " primes is ", sumPrimes(10));

function sumPrimes(n) { var foundPrimes = 0; var i = 2; var sum = 0;

while(foundPrimes < n)
{
    if (isPrime(i))
    {
        foundPrimes++;
        sum += i;
    }

    i++;
}

return sum;

}

// Returns true if number n is prime function isPrime(n) { if (n < 2) return false;

if (n == 2)
    return true;

var maxDiv = Math.sqrt(n);

for(var i = 2; i <= maxDiv; i++)
{
    if (n % i === 0)
    {
        return false;
    }
}

return true;

} ```

Coding challenge #29: Print the distance between the first 100 prime numbers

https://codeguppy.com/code.html?xKQEeKYF1LxZhDhwOH7V

```js printDistances(100);

// Print distances between the first n prime numbers function printDistances(n) { var lastPrime = 2; var i = lastPrime + 1; var foundPrimes = 1;

while(foundPrimes < n)
{
    if (isPrime(i))
    {
        console.log(i - lastPrime, "\t", i, " - ", lastPrime);

        foundPrimes++;
        lastPrime = i;
    }

    i++;
}

}

// Returns true if number n is prime function isPrime(n) { if (n < 2) return false;

if (n == 2)
    return true;

var maxDiv = Math.sqrt(n);

for(var i = 2; i <= maxDiv; i++)
{
    if (n % i === 0)
    {
        return false;
    }
}

return true;

} ```

Coding challenge #30: Create a function that will add two positive numbers of indefinite size. The numbers are received as strings and the result should be also provided as string.

Solution 1

https://codeguppy.com/code.html?v5A0QBsdHaiAVA2CPN5y

```js var n1 = "2909034221912398942349"; var n2 = "1290923909029309499"; var sum = add(n1, n2);

console.log(n1, "\n", n2, "\n", sum);

function add(sNumber1, sNumber2) { var s = ""; var carry = 0;

var maxSize = Math.max(sNumber1.length, sNumber2.length);

for(var i = 0; i < maxSize; i++)
{
    var digit1 = digitFromRight(sNumber1, i);
    var digit2 = digitFromRight(sNumber2, i);

    var sum = digit1 + digit2;

    var digitSum = sum % 10;
    digitSum += carry;
    s = digitSum.toString() + s;

    carry = sum >= 10 ? 1 : 0;
}

if (carry > 0)
    s = carry + s;

return s;

}

function digitFromRight(s, digitNo) { if (digitNo >= s.length) return 0;

var char = s[ s.length - 1 - digitNo ];
return parseInt(char);

} ```

Coding challenge #30: Create a function that will add two positive numbers of indefinite size. The numbers are received as strings and the result should be also provided as string.

Solution 2

https://codeguppy.com/code.html?yMQXcPgfrYxuaIxqQmZc

```js var n1 = "2909034221912398942349"; var n2 = "1290923909029309499"; var sum = add(n1, n2);

console.log(n1); console.log(n2); console.log(sum);

function add(sNumber1, sNumber2) { var maxSize = Math.max(sNumber1.length, sNumber2.length);

var s1 = sNumber1.padStart(maxSize, "0");
var s2 = sNumber2.padStart(maxSize, "0");

var s = "";
var carry = 0;

for(var i = maxSize - 1; i >= 0; i--)
{
    var digit1 = parseInt(s1[i]);
    var digit2 = parseInt(s2[i]);

    var sum = digit1 + digit2;

    var digitSum = sum % 10;
    digitSum += carry;
    s = digitSum.toString() + s;

    carry = sum >= 10 ? 1 : 0;
}

if (carry > 0)
    s = carry + s;

return s;

} ```

Others coding challenges to try on your own:

Create a function that will return the number of words in a text
Create a function that will capitalize the first letter of each word in a text
Calculate the sum of numbers received in a comma delimited string
Create a function that returns the number of occurrences of each word inside a text. The return will be an array with objects inside {word, count}
Create a function to convert a CSV text to a “bi-dimensional” array
Create a function that converts a string to an array of characters
Create a function that will convert a string in an array containing the ASCII codes of each character
Create a function that will convert an array containing ASCII codes in a string
Implement the Caesar cypher
Implement the bubble sort algorithm for an array of numbers
Create a function to calculate the distance between two points defined by their x, y coordinates
Create a function that will return a Boolean value indicating if two circles defined by center coordinates and radius are intersecting
Create a function that will receive a bi-dimensional array as argument and a number and will extract as a unidimensional array the column specified by the number
Create a function that will convert a string containing a binary number into a number
Create a function to calculate the sum of all the numbers in a jagged array (contains numbers or other arrays of numbers on an unlimited number of levels)
Find the maximum number in a jagged array of numbers or array of numbers
Deep copy a jagged array with numbers or other arrays in a new array
Create a function to return the longest word in a string
Shuffle an array of strings
Create a function that will receive n as argument and return an array of n random numbers from 1 to n. The numbers should be unique inside the array.
Find the frequency of letters inside a string. Return the result as an array of arrays. Each subarray has 2 elements: letter and number of occurrences.
Calculate Fibonacci(500) with high precision (all digits)
Calculate 70! with high precision (all digits)

If you like this kind of challenges, please follow @codeguppy on Twitter where coding challenges and other news are sometimes posted (even in graphical form).

Comments section

naveenkumar337

•

May 1, 2024

Hello,

Create a function that will add two positive numbers of indefinite size. The numbers are received as strings and the result should be also provided as a string.

solution 1

Can you explain to me why using carry(why need to take 1 if sum greater then 10)? and why we have to do mudular division and why need to add digitsum and carry

0 Replies

Micro Coding Challenges - with solutions

codeguppy

Coding challenge #1: Print numbers from 1 to 10

Coding challenge #2: Print the odd numbers less than 100

Coding challenge #3: Print the multiplication table with 7

Coding challenge #4: Print all the multiplication tables with numbers from 1 to 10

Coding challenge #5: Calculate the sum of numbers from 1 to 10

Coding challenge #6: Calculate 10!

Coding challenge #7: Calculate the sum of even numbers greater than 10 and less than 30

Coding challenge #8: Create a function that will convert from Celsius to Fahrenheit

Coding challenge #9: Create a function that will convert from Fahrenheit to Celsius

Coding challenge #10: Calculate the sum of numbers in an array of numbers

Coding challenge #11: Calculate the average of the numbers in an array of numbers

Coding challenge #12: Create a function that receives an array of numbers and returns an array containing only the positive numbers

Coding challenge #12: Create a function that receives an array of numbers and returns an array containing only the positive numbers

Coding challenge #12: Create a function that receives an array of numbers and returns an array containing only the positive numbers

Coding challenge #13: Find the maximum number in an array of numbers

Coding challenge #14: Print the first 10 Fibonacci numbers without recursion

Coding challenge #15: Create a function that will find the nth Fibonacci number using recursion

Coding challenge #16: Create a function that will return a Boolean specifying if a number is prime

Coding challenge #17: Calculate the sum of digits of a positive integer number

Coding challenge #18: Print the first 100 prime numbers

Coding challenge #19: Create a function that will return in an array the first "nPrimes" prime numbers greater than a particular number "startAt"

Coding challenge #20: Rotate an array to the left 1 position

Coding challenge #21: Rotate an array to the right 1 position

Coding challenge #22: Reverse an array

Coding challenge #23: Reverse a string

Coding challenge #25: Create a function that will receive two arrays of numbers as arguments and return an array composed of all the numbers that are either in the first array or second array but not in both

Coding challenge #26: Create a function that will receive two arrays and will return an array with elements that are in the first array but not in the second

Coding challenge #27: Create a function that will receive an array of numbers as argument and will return a new array with distinct elements

Coding challenge #27: Create a function that will receive an array of numbers as argument and will return a new array with distinct elements

Coding challenge #28: Calculate the sum of first 100 prime numbers

Coding challenge #29: Print the distance between the first 100 prime numbers

Coding challenge #30: Create a function that will add two positive numbers of indefinite size. The numbers are received as strings and the result should be also provided as string.

Coding challenge #30: Create a function that will add two positive numbers of indefinite size. The numbers are received as strings and the result should be also provided as string.

Comments section

naveenkumar337

Adrian

Teaching Coding To Kids, Teens And Creative Adults At Https://Codeguppy.Com

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