JavaScript Coding Challenges for Beginners
Mastering these coding challenges may not get you a job at Google... but you'll be one step closer to building your own JavaScript game at codeguppy.com
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The coding challenges in this article are intended for code newbies, therefore the solutions are implemented using only simple / classical programming elements. Each solution is acompanied by an online link that helps you quickly run it in a code playground.
If you prefer to open all solutions in a single, unified coding playgroud please open the 50 Coding Challenges project.
The code is making use of the codeguppy specific function println() to print the results. If you want to run these solutions outside CodeGuppy, just replace println() with console.log() then run them using your browser console tool or node.js.
Coding challenge #1: Print numbers from 1 to 10
for(let i = 1; i <= 10; i++)
{
println(i);
}
Coding challenge #2: Print the odd numbers less than 100
for(let i = 1; i <= 100; i += 2)
{
println(i);
}
Coding challenge #3: Print the multiplication table with 7
for(let i = 1; i <= 10; i++)
{
let row = "7 * " + i + " = " + 7 * i;
println(row);
}
Coding challenge #4: Print all the multiplication tables with numbers from 1 to 10
for(let i = 1; i <= 10; i++)
{
printTable(i);
println("");
}
function printTable(n)
{
for(let i = 1; i <= 10; i++)
{
let row = n + " * " + i + " = " + n * i;
println(row);
}
}
Coding challenge #5: Calculate the sum of numbers from 1 to 10
let sum = 0;
for(let i = 1; i <= 10; i++)
{
sum += i;
}
println(sum);
Coding challenge #6: Calculate 10!
let prod = 1;
for(let i = 1; i <= 10; i++)
{
prod *= i;
}
println(prod);
Coding challenge #7: Calculate the sum of odd numbers greater than 10 and less than 30
let sum = 0;
for(let i = 11; i <= 30; i += 2)
{
sum += i;
}
println(sum);
Coding challenge #8: Create a function that will convert from Celsius to Fahrenheit
function celsiusToFahrenheit(n)
{
return n * 1.8 + 32;
}
let r = celsiusToFahrenheit(20);
println(r);
Coding challenge #9: Create a function that will convert from Fahrenheit to Celsius
function fahrenheitToCelsius(n)
{
return (n - 32) / 1.8;
}
let r = fahrenheitToCelsius(68);
println(r);
Coding challenge #10: Calculate the sum of numbers in an array of numbers
function sumArray(ar)
{
let sum = 0;
for(let i = 0; i < ar.length; i++)
{
sum += ar[i];
}
return sum;
}
let ar = [2, 3, -1, 5, 7, 9, 10, 15, 95];
let sum = sumArray(ar);
println(sum);
Coding challenge #11: Calculate the average of the numbers in an array of numbers
function averageArray(ar)
{
let n = ar.length;
let sum = 0;
for(let i = 0; i < n; i++)
{
sum += ar[i];
}
return sum / n;
}
let ar = [1, 3, 9, 15, 90];
let avg = averageArray(ar);
println("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
function getPositives(ar)
{
let ar2 = [];
for(let i = 0; i < ar.length; i++)
{
let el = ar[i];
if (el >= 0)
{
ar2.push(el);
}
}
return ar2;
}
let ar = [-5, 10, -3, 12, -9, 5, 90, 0, 1];
let ar2 = getPositives(ar);
println(ar2);
Coding challenge #12: Create a function that receives an array of numbers and returns an array containing only the positive numbers
Solution 2
function getPositives(ar)
{
let ar2 = [];
for(let el of ar)
{
if (el >= 0)
{
ar2.push(el);
}
}
return ar2;
}
let ar = [-5, 10, -3, 12, -9, 5, 90, 0, 1];
let ar2 = getPositives(ar);
println(ar2);
Coding challenge #12: Create a function that receives an array of numbers and returns an array containing only the positive numbers
Solution 3
function getPositives(ar)
{
return ar.filter(el => el >= 0);
}
let ar = [-5, 10, -3, 12, -9, 5, 90, 0, 1];
let ar2 = getPositives(ar);
println(ar2);
Coding challenge #13: Find the maximum number in an array of numbers
function findMax(ar)
{
let max = ar[0];
for(let i = 0; i < ar.length; i++)
{
if (ar[i] > max)
{
max = ar[i];
}
}
return max;
}
let ar = [-5, 10, -3, 12, -9, 5, 90, 0, 1];
let max = findMax(ar);
println("Max: ", max);
Coding challenge #14: Print the first 10 Fibonacci numbers without recursion
let f0 = 0;
println(f0);
let f1 = 1;
println(f1);
for(let i = 2; i < 10; i++)
{
let fi = f1 + f0;
println(fi);
f0 = f1;
f1 = fi;
}
Coding challenge #15: Create a function that will find the nth Fibonacci number using recursion
function findFibonacci(n)
{
if (n == 0)
return 0;
if (n == 1)
return 1;
return findFibonacci(n - 1) + findFibonacci(n - 2);
}
let n = findFibonacci(10);
println(n);
Coding challenge #16: Create a function that will return a Boolean specifying if a number is prime
function isPrime(n)
{
if (n < 2)
return false;
if (n == 2)
return true;
let maxDiv = Math.sqrt(n);
for(let i = 2; i <= maxDiv; i++)
{
if (n % i == 0)
{
return false;
}
}
return true;
}
println(2, " is prime? ", isPrime(2));
println(3, " is prime? ", isPrime(3));
println(4, " is prime? ", isPrime(4));
println(5, " is prime? ", isPrime(5));
println(9, " is prime? ", isPrime(9));
Coding challenge #17: Calculate the sum of digits of a positive integer number
function sumDigits(n)
{
let s = n.toString();
let sum = 0;
for(let char of s)
{
let digit = parseInt(char);
sum += digit;
}
return sum;
}
let sum = sumDigits(1235231);
println("Sum: ", sum);
Coding challenge #18: Print the first 100 prime numbers
printPrimes(100);
// Function prints the first nPrimes numbers
function printPrimes(nPrimes)
{
let n = 0;
let i = 2;
while(n < nPrimes)
{
if (isPrime(i))
{
println(n, " --> ", i);
n++;
}
i++;
}
}
// Returns true if a number is prime
function isPrime(n)
{
if (n < 2)
return false;
if (n == 2)
return true;
let maxDiv = Math.sqrt(n);
for(let 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"
println(getPrimes(10, 100));
function getPrimes(nPrimes, startAt)
{
let ar = [];
let 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;
let maxDiv = Math.sqrt(n);
for(let i = 2; i <= maxDiv; i++)
{
if (n % i == 0)
{
return false;
}
}
return true;
}
Coding challenge #20: Rotate an array to the left 1 position
let ar = [1, 2, 3];
rotateLeft(ar);
println(ar);
function rotateLeft(ar)
{
let first = ar.shift();
ar.push(first);
}
Coding challenge #21: Rotate an array to the right 1 position
let ar = [1, 2, 3];
rotateRight(ar);
println(ar);
function rotateRight(ar)
{
let last = ar.pop();
ar.unshift(last);
}
Coding challenge #22: Reverse an array
let ar = [1, 2, 3];
let ar2 = reverseArray(ar);
println(ar2);
function reverseArray(ar)
{
let ar2 = [];
for(let i = ar.length - 1; i >= 0; i--)
{
ar2.push(ar[i]);
}
return ar2;
}
Coding challenge #23: Reverse a string
let s = reverseString("JavaScript");
println(s);
function reverseString(s)
{
let s2 = "";
for(let i = s.length - 1; i >= 0; i--)
{
let 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
let ar1 = [1, 2, 3];
let ar2 = [4, 5, 6];
let ar = mergeArrays(ar1, ar2);
println(ar);
function mergeArrays(ar1, ar2)
{
let 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
let ar1 = [1, 2, 3, 10, 5, 3, 14];
let ar2 = [1, 4, 5, 6, 14];
let ar = mergeExclusive(ar1, ar2);
println(ar);
function mergeExclusive(ar1, ar2)
{
let 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
let ar1 = [1, 2, 3, 10, 5, 3, 14];
let ar2 = [-1, 4, 5, 6, 14];
let ar = mergeLeft(ar1, ar2);
println(ar);
function mergeLeft(ar1, ar2)
{
let 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
let ar = getDistinctElements([1, 2, 3, 6, -1, 2, 9, 7, 10, -1, 100]);
println(ar);
function getDistinctElements(ar)
{
let 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
let ar = getDistinctElements([1, 2, 3, 6, -1, 2, 9, 7, 10, -1, 100]);
println(ar);
function getDistinctElements(ar)
{
let ar2 = [];
let 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(let i = fromIndex; i <= toIndex; i++)
{
if (ar[i] === n)
return true;
}
return false;
}
Coding challenge #28: Calculate the sum of first 100 prime numbers
let n = 10;
println("Sum of first ", n, " primes is ", sumPrimes(10));
function sumPrimes(n)
{
let foundPrimes = 0;
let i = 2;
let 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;
let maxDiv = Math.sqrt(n);
for(let 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
printDistances(100);
// Print distances between the first n prime numbers
function printDistances(n)
{
let lastPrime = 2;
let i = lastPrime + 1;
let foundPrimes = 1;
while(foundPrimes < n)
{
if (isPrime(i))
{
println(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;
let maxDiv = Math.sqrt(n);
for(let i = 2; i <= maxDiv; i++)
{
if (n % i === 0)
{
return false;
}
}
return true;
}
Coding challenge #30-a: 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
let n1 = "2909034221912398942349";
let n2 = "1290923909029309499";
let sum = add(n1, n2);
println(n1, "\n", n2, "\n", sum);
function add(sNumber1, sNumber2)
{
let s = "";
let carry = 0;
let maxSize = Math.max(sNumber1.length, sNumber2.length);
for(let i = 0; i < maxSize; i++)
{
let digit1 = digitFromRight(sNumber1, i);
let digit2 = digitFromRight(sNumber2, i);
let sum = digit1 + digit2 + carry;
let digitSum = sum % 10;
carry = sum >= 10 ? 1 : 0;
s = digitSum.toString() + s;
}
if (carry > 0)
s = carry + s;
return s;
}
function digitFromRight(s, digitNo)
{
if (digitNo >= s.length)
return 0;
let char = s[ s.length - 1 - digitNo ];
return parseInt(char);
}
Coding challenge #30-b: 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
let n1 = "2909034221912398942349";
let n2 = "1290923909029309499";
let sum = add(n1, n2);
println(n1);
println(n2);
println(sum);
function add(sNumber1, sNumber2)
{
let maxSize = Math.max(sNumber1.length, sNumber2.length);
let s1 = sNumber1.padStart(maxSize, "0");
let s2 = sNumber2.padStart(maxSize, "0");
let s = "";
let carry = 0;
for(let i = maxSize - 1; i >= 0; i--)
{
let digit1 = parseInt(s1[i]);
let digit2 = parseInt(s2[i]);
let sum = digit1 + digit2 + carry;
let digitSum = sum % 10;
carry = sum >= 10 ? 1 : 0;
s = digitSum.toString() + s;
}
if (carry > 0)
s = carry + s;
return s;
}
Coding challenge #31a. Create a function that will return the number of words in a text
// Solution 1
function countWords(text)
{
let wasSeparator = true;
let words = 0;
for(let c of text)
{
// if current character is separator then advance and
// set that the previous character was separator
if (isSeparator(c))
{
wasSeparator = true;
continue;
}
// if current character is not separator
// ... but if previous was separator...
if (wasSeparator)
{
words++;
wasSeparator = false;
}
}
return words;
}
function isSeparator(c)
{
let separators = [" ", "\t", "\n", "\r", ",", ";", ".", "!", "?"];
return separators.includes(c);
}
println(countWords(""));
println(countWords(" "));
println(countWords("JavaScript!!! "));
println(countWords(" JavaScript"));
println(countWords(" JavaScript is cool "));
println(countWords("I like to learn JavaScript with codeguppy"));
Coding challenge #31b. Create a function that will return the number of words in a text
// Solution 2
function countWords(text)
{
let words = 0;
if (text.length > 0 && !isSeparator(text[0]))
words++;
for(let i = 1; i < text.length; i++)
{
let currChr = text[i];
let prevChr = text[i - 1];
if (!isSeparator(currChr) && isSeparator(prevChr))
{
words++;
}
}
return words;
}
function isSeparator(c)
{
let separators = [" ", "\t", "\n", "\r", ",", ";", ".", "!", "?"];
return separators.includes(c);
}
println(countWords(""));
println(countWords(" "));
println(countWords("JavaScript!!! "));
println(countWords(" JavaScript"));
println(countWords(" JavaScript is cool "));
println(countWords("I like to learn JavaScript with codeguppy"));
Coding challenge #32. Create a function that will capitalize the first letter of each word in a text
println(captializeWords("Create a function that will capitalize the first letter of each word in a text"));
function captializeWords(text)
{
let text2 = "";
for(let i = 0; i < text.length; i++)
{
let currChr = text[i];
let prevChr = i > 0 ? text[i - 1] : " ";
if (!isSeparator(currChr) && isSeparator(prevChr))
{
currChr = currChr.toUpperCase();
}
text2 += currChr;
}
return text2;
}
function isSeparator(c)
{
let separators = [" ", "\t", "\n", "\r", ",", ";", ".", "!", "?"];
return separators.includes(c);
}
Coding challenge #33. Calculate the sum of numbers received in a comma delimited string
println(sumCSV("1.5, 2.3, 3.1, 4, 5.5, 6, 7, 8, 9, 10.9"));
function sumCSV(s)
{
let ar = s.split(",");
let sum = 0;
for(let n of ar)
{
sum += parseFloat(n);
}
return sum;
}
Coding challenge #34. Create a function that will return an array with words inside a text
let text = "Create a function, that will return an array (of string), with the words inside the text";
println(getWords(text));
function getWords(text)
{
let startWord = -1;
let ar = [];
for(let i = 0; i <= text.length; i++)
{
let c = i < text.length ? text[i] : " ";
if (!isSeparator(c) && startWord < 0)
{
startWord = i;
}
if (isSeparator(c) && startWord >= 0)
{
let word = text.substring(startWord, i);
ar.push(word);
startWord = -1;
}
}
return ar;
}
function isSeparator(c)
{
let separators = [" ", "\t", "\n", "\r", ",", ";", ".", "!", "?", "(", ")"];
return separators.includes(c);
}
Coding challenge #35. Create a function to convert a CSV text to a “bi-dimensional” array
let data = "John;Smith;954-000-0000\nMich;Tiger;305-000-0000\nMonique;Vasquez;103-000-0000";
let ar = csvToArray(data);
println(JSON.stringify(ar));
function csvToArray(data)
{
let arLines = data.split("\n");
for(let i = 0; i < arLines.length; i++)
{
let arLine = arLines[i].split(";");
arLines[i] = arLine;
}
return arLines;
}
Coding challenge #36. Create a function that converts a string to an array of characters
println(getChars("I like JavaScript"));
function getChars(s)
{
return Array.from(s);
}
Coding challenge #37. Create a function that will convert a string in an array containing the ASCII codes of each character
println(getCharCodes("I like JavaScript"));
function getCharCodes(s)
{
let ar = [];
for(let i = 0; i < s.length; i++)
{
let code = s.charCodeAt(i);
ar.push(code);
}
return ar;
}
Coding challenge #38. Create a function that will convert an array containing ASCII codes in a string
println(codesToString([73,32,108,105,107,101,32,74,97,118,97,83,99,114,105,112,116]));
function codesToString(ar)
{
return String.fromCharCode(...ar);
}
Coding challenge #39. Implement the Caesar cypher
let text = "I LOVE JAVASCRIPT";
let textEnc = encrypt(text, 13);
let textDec = decrypt(textEnc, 13);
println(text);
println(textEnc);
println(textDec);
// Decrypt a message by using the same encrypt function
// ... but using the inverse of the key (e.g. rotate in the other direction)
function decrypt(msg, key)
{
return encrypt(msg, key * -1);
}
// Function will implement Caesar Cipher to
// encrypt / decrypt the msg by shifting the letters
// of the message acording to the key
function encrypt(msg, key)
{
let encMsg = "";
for(let i = 0; i < msg.length; i++)
{
let code = msg.charCodeAt(i);
// Encrypt only letters in 'A' ... 'Z' interval
if (code >= 65 && code <= 65 + 26 - 1)
{
code -= 65;
code = mod(code + key, 26);
code += 65;
}
encMsg += String.fromCharCode(code);
}
return encMsg;
}
// Modulo function: n mod p
function mod(n, p)
{
if ( n < 0 )
n = p - Math.abs(n) % p;
return n % p;
}
Coding challenge #40. Implement the bubble sort algorithm for an array of numbers
let ar = [23, 1000, 1, -1, 8, 3];
println(ar);
bubbleSort(ar);
println(ar);
function bubbleSort(ar)
{
let shouldSort = true;
let length = ar.length;
while(shouldSort)
{
shouldSort = false;
length--;
for(let i = 0; i < length; i++)
{
let a = ar[i];
if ( a > ar[i+1] )
{
ar[i] = ar[i+1];
ar[i+1] = a;
shouldSort = true;
}
}
}
}
Coding challenge #41. Create a function to calculate the distance between two points defined by their x, y coordinates
println(getDistance(100, 100, 400, 300));
function getDistance(x1, y1, x2, y2)
{
let l1 = x2 - x1;
let l2 = y2 - y1;
return Math.sqrt(l1 * l1 + l2 * l2);
}
Coding challenge #42. Create a function that will return a Boolean value indicating if two circles defined by center coordinates and radius are intersecting
println(collisionCircleCircle(200, 200, 100, 300, 300, 50));
function collisionCircleCircle(circle1X, circle1Y, circle1R, circle2X, circle2Y, circle2R)
{
return getDistance(circle1X, circle1Y, circle2X, circle2Y) <= circle1R + circle2R;
}
// Calculate the distance between the two specified points
function getDistance(x1, y1, x2, y2)
{
let l1 = x2 - x1;
let l2 = y2 - y1;
return Math.sqrt(l1 * l1 + l2 * l2);
}
Coding challenge 43. 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
let ar = [ ["John", 120],
["Jane", 115],
["Thomas", 123],
["Mel", 112],
["Charley", 122]
];
let numbers = extractCol(ar, 1);
println(numbers);
function extractCol(ar, colNo)
{
let arCol = [];
for(let i = 0; i < ar.length; i++)
{
arCol.push(ar[i][colNo]);
}
return arCol;
}
Coding challenge #44. Create a function that will convert a string containing a binary number into a number
println(binaryToNumber("11111111"));
function binaryToNumber(sBinary)
{
return parseInt(sBinary, 2);
}
Coding challenge #45. Create a function to calculate the sum of all the numbers in a jagged array (array contains numbers or other arrays of numbers on an unlimited number of levels)
let ar = [1, 2, [15, [23], [5, 12]], [100]];
println(sumArray(ar));
function sumArray(ar)
{
let sum = 0;
for(let el of ar)
{
if (Array.isArray(el))
{
el = sumArray(el);
}
sum += el;
}
return sum;
}
Coding challenge #46-a. Find the maximum number in a jagged array of numbers or array of numbers
// Solution 1
let ar = [2, 4, 10, [12, 4, [100, 99], 4], [3, 2, 99], 0];
let max = findMax(ar);
println("Max = ", max);
// Use recursion to find the maximum numeric value in an array of arrays
function findMax(ar)
{
let max = -Infinity;
// Cycle through all the elements of the array
for(let i = 0; i < ar.length; i++)
{
let el = ar[i];
// If an element is of type array then invoke the same function
// to find out the maximum element of that subarray
if ( Array.isArray(el) )
{
el = findMax( el );
}
if ( el > max )
{
max = el;
}
}
return max;
}
Coding challenge #46-b. Find the maximum number in a jagged array of numbers or array of numbers
// Solution 2
let ar = [2, 4, 10, [12, 4, [100, 99], 4], [3, 2, 99], 0];
let max = findMax(ar);
println("Max = ", max);
// Use a stack to find the maximum numeric value in an array of arrays
function findMax(arElements)
{
let max = -Infinity;
// This is the stack on which will put the first array and then
// all the other sub-arrays that we find as we traverse an array
let arrays = [];
arrays.push(arElements);
// Loop as long as are arrays added to the stack for processing
while(arrays.length > 0)
{
// Extract an array from the stack
ar = arrays.pop();
// ... and loop through its elements
for(let i = 0; i < ar.length; i++)
{
let el = ar[i];
// If an element is of type array, we'll add it to stack
// to be processed later
if ( Array.isArray(el) )
{
arrays.push(el);
continue;
}
if ( el > max )
{
max = el;
}
}
}
return max;
}
Coding challenge #47. Deep copy a jagged array with numbers or other arrays in a new array
let ar1 = [2, 4, 10, [12, 4, [100, 99], 4], [3, 2, 99], 0];
let ar2 = copyArray(ar1);
println(ar2);
function copyArray(ar)
{
let ar2 = [];
for(let el of ar)
{
if (Array.isArray(el))
{
el = copyArray(el);
}
ar2.push(el);
}
return ar2;
}
Coding challenge #48. Create a function to return the longest word(s) in a string
let text = "Create a function to return the longest word(s) in a sentance.";
println(getLongestWords(text));
function getLongestWords(text)
{
let words = getWords(text);
let maxSize = 0;
let maxPositions = [];
for(let i = 0; i < words.length; i++)
{
let currWordSize = words[i].length;
if (currWordSize > maxSize)
{
maxSize = currWordSize;
maxPositions = [ i ];
}
else if (currWordSize === maxSize)
{
maxPositions.push(i);
}
}
return getElements(words, maxPositions);
}
// Get only the elements from specified positions from the array
function getElements(ar, arPositions)
{
let arNew = [];
for(let pos of arPositions)
{
arNew.push(ar[pos]);
}
return arNew;
}
// Returns an array with the words from specified text
function getWords(text)
{
let startWord = -1;
let ar = [];
for(let i = 0; i <= text.length; i++)
{
let c = i < text.length ? text[i] : " ";
if (!isSeparator(c) && startWord < 0)
{
startWord = i;
}
if (isSeparator(c) && startWord >= 0)
{
let word = text.substring(startWord, i);
ar.push(word);
startWord = -1;
}
}
return ar;
}
function isSeparator(c)
{
let separators = [" ", "\t", "\n", "\r", ",", ";", ".", "!", "?", "(", ")"];
return separators.includes(c);
}
Coding challenge #49. Shuffle an array of strings
let ar = ["Shuffle", "an", "array", "of", "strings"];
println(shuffleArray(ar));
// Shuffle array implemented using Fisher–Yates shuffle algorithm
function shuffleArray(ar)
{
for(let i = ar.length - 1; i > 0; i--)
{
let j = randomInt(0, i - 1);
let t = ar[i];
ar[i] = ar[j];
ar[j] = t;
}
return ar;
}
// Get a random int between min and max (both included)
function randomInt(min, max)
{
return Math.floor(Math.random() * (max - min + 1) ) + min;
}
Coding challenge #50. Create a function that will receive n as argument and return an array of n unique random numbers from 1 to n.
println(getRandomNumbers(10));
function getRandomNumbers(n)
{
let ar = [];
for(let i = 1; i <= n; i++)
{
ar.push(i);
}
shuffleArray(ar);
return ar;
}
// Shuffle array implemented using Fisher–Yates shuffle algorithm
function shuffleArray(ar)
{
for(let i = ar.length - 1; i > 0; i--)
{
let j = randomInt(0, i - 1);
let t = ar[i];
ar[i] = ar[j];
ar[j] = t;
}
return ar;
}
// Get a random int between min and max (both included)
function randomInt(min, max)
{
return Math.floor(Math.random() * (max - min + 1) ) + min;
}
Coding challenge #51. Find the frequency of characters inside a string. Return the result as an array of objects. Each object has 2 fields: character and number of occurrences.
let ar = getCharFrequency("Find the frequency of characters inside a string");
println(JSON.stringify(ar));
function getCharFrequency(text)
{
let ar = [];
for(let chr of text)
{
updateFrequency(ar, chr);
}
return ar;
}
function updateFrequency(ar, chr)
{
for(let el of ar)
{
if (el.chr === chr)
{
el.count++;
}
}
ar.push({ chr : chr, count : 1 });
}
Coding challenge #52. Calculate Fibonacci(500) with high precision (all digits)
println(fibonacci(500));
function fibonacci(n)
{
if (n === 0)
return "0";
if (n === 1)
return "1";
let n1 = "0";
let n2 = "1";
for(let i = 2; i <= n; i++)
{
let sum = add(n1, n2);
n1 = n2;
n2 = sum;
}
return n2;
}
function add(sNumber1, sNumber2)
{
let maxSize = Math.max(sNumber1.length, sNumber2.length);
let s1 = sNumber1.padStart(maxSize, "0");
let s2 = sNumber2.padStart(maxSize, "0");
let s = "";
let carry = 0;
for(let i = maxSize - 1; i >= 0; i--)
{
let digit1 = parseInt(s1[i]);
let digit2 = parseInt(s2[i]);
let sum = digit1 + digit2 + carry;
let digitSum = sum % 10;
carry = sum >= 10 ? 1 : 0;
s = digitSum.toString() + s;
}
if (carry > 0)
s = carry + s;
return s;
}
Coding challenge #53. Calculate 70! with high precision (all digits)
println(factorial(70));
// Calculate factorial(n) ... using big number calculations
function factorial(n)
{
let prod = "1";
for(let i = 2; i <= n; i++)
{
prod = mult(prod, i.toString());
}
return prod;
}
// Multiplies sNumber1 * sNumber2
// Each number is provided as string
function mult(sNumber1, sNumber2)
{
// Calculate partial results according to multiplication algorithm
let partialResults = [];
for(let i = sNumber2.length - 1; i >= 0; i--)
{
let digit = parseInt(sNumber2[i]);
let partialResult = multDigit(sNumber1, digit);
partialResult += "0".repeat(partialResults.length);
partialResults.push(partialResult);
}
// Sum partial results to obtain the product
let sum = "";
for(let r of partialResults)
{
sum = add(sum, r);
}
return sum;
}
// Multiplies number sNumber (as string) with a single digit number
function multDigit(sNumber, digit)
{
let p = "";
let carry = 0;
for(let i = sNumber.length - 1; i >= 0; i--)
{
let numberDigit = parseInt(sNumber[i]);
let prod = digit * numberDigit + carry;
let prodDigit = prod % 10;
carry = Math.floor(prod / 10);
p = prodDigit.toString() + p;
}
if (carry > 0)
p = carry + p;
return p;
}
function add(sNumber1, sNumber2)
{
let maxSize = Math.max(sNumber1.length, sNumber2.length);
let s1 = sNumber1.padStart(maxSize, "0");
let s2 = sNumber2.padStart(maxSize, "0");
let s = "";
let carry = 0;
for(let i = maxSize - 1; i >= 0; i--)
{
let digit1 = parseInt(s1[i]);
let digit2 = parseInt(s2[i]);
let sum = digit1 + digit2 + carry;
let digitSum = sum % 10;
carry = sum >= 10 ? 1 : 0;
s = digitSum.toString() + s;
}
if (carry > 0)
s = carry + s;
return s;
}
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