Intermediate Algorithm Scripting (ex. 9 to 12)

Author: hgonzaga

Diff for: 09-intermediate-algorithm-scripting/09-missing-letters.js

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+/*
+Missing letters:
+Find the missing letter in the passed letter range and return it.
+If all letters are present in the range, return undefined.
+
+- fearNotLetter("abce") should return the string d.
+- fearNotLetter("abcdefghjklmno") should return the string i.
+- fearNotLetter("stvwx") should return the string u.
+- fearNotLetter("bcdf") should return the string e.
+- fearNotLetter("abcdefghijklmnopqrstuvwxyz") should return undefined.
+*/
+function fearNotLetter(str) {
+    const strStartingCharCode = str[0].charCodeAt(0);
+    for (let i = strStartingCharCode; i < strStartingCharCode + str.length; i++) {
+        const alphabetCharacter = String.fromCharCode(i);
+        if (str.charAt(i - strStartingCharCode) !== alphabetCharacter) {
+            return alphabetCharacter;
+        }
+    }
+    return undefined;
+}
+
+console.log(fearNotLetter("abce"));
+console.log(fearNotLetter("abcdefghjklmno"));
+console.log(fearNotLetter("stvwx"));
+console.log(fearNotLetter("bcdf"));
+console.log(fearNotLetter("abcdefghijklmnopqrstuvwxyz"));

Diff for: 09-intermediate-algorithm-scripting/10-sorted-union.js

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+/*
+Sorted Union:
+Write a function that takes two or more arrays and returns a new array of unique values in the order of the original provided arrays.
+In other words, all values present from all arrays should be included in their original order, but with no duplicates in the final array.
+The unique numbers should be sorted by their original order, but the final array should not be sorted in numerical order.
+Check the assertion tests for examples.
+
+- uniteUnique([1, 3, 2], [5, 2, 1, 4], [2, 1]) should return [1, 3, 2, 5, 4].
+- uniteUnique([1, 2, 3], [5, 2, 1]) should return [1, 2, 3, 5].
+- uniteUnique([1, 2, 3], [5, 2, 1, 4], [2, 1], [6, 7, 8]) should return [1, 2, 3, 5, 4, 6, 7, 8].
+*/
+function uniteUnique(arr) {
+    const args = [...arguments];
+    const output = [];
+
+    for (const innerArray of args) {
+        for (const item of innerArray) {
+            if (!output.includes(item)) {
+                output.push(item);
+            }
+        }
+    }
+
+    return output;
+}
+
+console.log(uniteUnique([1, 3, 2], [5, 2, 1, 4], [2, 1]));
+console.log(uniteUnique([1, 2, 3], [5, 2, 1]));
+console.log(uniteUnique([1, 2, 3], [5, 2, 1, 4], [2, 1], [6, 7, 8]));

Diff for: 09-intermediate-algorithm-scripting/11-convert-html-entities.js

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+/*
+Convert HTML Entities
+Convert the characters &, <, >, " (double quote), and ' (apostrophe), in a string to their corresponding HTML entities.
+
+- convertHTML("Dolce & Gabbana") should return the string Dolce &amp; Gabbana.
+- convertHTML("Hamburgers < Pizza < Tacos") should return the string Hamburgers &lt; Pizza &lt; Tacos.
+- convertHTML("Sixty > twelve") should return the string Sixty &gt; twelve.
+- convertHTML('Stuff in "quotation marks"') should return the string Stuff in &quot;quotation marks&quot;.
+- convertHTML("Schindler's List") should return the string Schindler&apos;s List.
+- convertHTML("<>") should return the string &lt;&gt;.
+- convertHTML("abc") should return the string abc.
+*/
+function convertHTML(str) {
+    const htmlEntities = {
+        "&": "&amp;",
+        "<": "&lt;",
+        ">": "&gt;",
+        '"': "&quot;",
+        "'": "&apos;"
+    };
+    return str.replace(/[&<>"']/g, match => htmlEntities[match]);
+}
+
+console.log(convertHTML("Dolce & Gabbana"));
+console.log(convertHTML("Hamburgers < Pizza < Tacos"));
+console.log(convertHTML("Sixty > twelve"));
+console.log(convertHTML('Stuff in "quotation marks"'));
+console.log(convertHTML("Schindler's List"));
+console.log(convertHTML("<>"));
+console.log(convertHTML("abc"));

Diff for: 09-intermediate-algorithm-scripting/12-sum-all-odd-fibonacci-numbers.js

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+/*
+Sum All Odd Fibonacci Numbers:
+Given a positive integer num, return the sum of all odd Fibonacci numbers that are less than or equal to num.
+The first two numbers in the Fibonacci sequence are 1 and 1.
+Every additional number in the sequence is the sum of the two previous numbers.
+The first six numbers of the Fibonacci sequence are 1, 1, 2, 3, 5 and 8.
+For example, sumFibs(10) should return 10 because all odd Fibonacci numbers less than or equal to 10 are 1, 1, 3, and 5.
+
+- sumFibs(1) should return a number.
+- sumFibs(1000) should return 1785.
+- sumFibs(4000000) should return 4613732.
+- sumFibs(4) should return 5.
+- sumFibs(75024) should return 60696.
+- sumFibs(75025) should return 135721.
+*/
+function sumFibs(num) {
+    const fibonacciSequence = [1, 1];
+    let lastFibonacciNumber = fibonacciSequence[fibonacciSequence.length - 1];
+
+    while (lastFibonacciNumber <= num) {
+        lastFibonacciNumber = fibonacciSequence[fibonacciSequence.length - 1];
+        const previousFibonacciNumber = fibonacciSequence[fibonacciSequence.length - 2];
+        const sumLastFibonacciNumbers = previousFibonacciNumber + lastFibonacciNumber;
+
+        if (sumLastFibonacciNumbers > num) {
+            break;
+        }
+
+        fibonacciSequence.push(sumLastFibonacciNumbers);
+    }
+
+    return fibonacciSequence
+        .filter(number => number % 2 !== 0)
+        .reduce((sum, b) => sum + b);
+}
+
+console.log(sumFibs(4));
+console.log(sumFibs(1));
+console.log(sumFibs(1000));
+console.log(sumFibs(4000000));
+console.log(sumFibs(75024));
+console.log(sumFibs(75025));

Diff for: 09-intermediate-algorithm-scripting/13-sum-all-primes.js

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+/*
+Sum All Primes:
+A prime number is a whole number greater than 1 with exactly two divisors: 1 and itself.
+For example, 2 is a prime number because it is only divisible by 1 and 2.
+In contrast, 4 is not prime since it is divisible by 1, 2 and 4.
+
+Rewrite sumPrimes so it returns the sum of all prime numbers that are less than or equal to num.
+
+- sumPrimes(10) should return a number.
+- sumPrimes(10) should return 17.
+- sumPrimes(977) should return 73156.
+*/

Diff for: 09-intermediate-algorithm-scripting/README.md

@@ -17,11 +17,11 @@ freeCodeCamp module description:
 - [X] [ 06 - Pig Latin](06-pig-latin.js)
 - [X] [ 07 - Search and Replace](07-search-and-replace.js)
 - [X] [ 08 - DNA Pairing](08-dna-pairing.js)
-- [ ] [ 09 - Missing letters]()
-- [ ] [ 10 - Sorted Union]()
-- [ ] [ 11 - Convert HTML Entities]()
-- [ ] [ 12 - Sum All Odd Fibonacci Numbers]()
-- [ ] [ 13 - Sum All Primes]()
+- [X] [ 09 - Missing letters](09-missing-letters.js)
+- [X] [ 10 - Sorted Union](10-sorted-union.js)
+- [X] [ 11 - Convert HTML Entities](11-convert-html-entities.js)
+- [X] [ 12 - Sum All Odd Fibonacci Numbers](12-sum-all-odd-fibonacci-numbers.js)
+- [ ] [ 13 - Sum All Primes](13-sum-all-primes.js)
 - [ ] [ 14 - Smallest Common Multiple]()
 - [ ] [ 15 - Drop it]()
 - [ ] [ 16 - Steamroller]()