feat(maths): adds prime sieve and generator

DIRECTORY.md

@@ -3,24 +3,79 @@
  * [Xor Cipher](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/ciphers/xor_cipher.ts)
 
 ## Data Structures
- * [Array Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/array_queue.ts)
- * [Linked Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/linked_queue.ts)
- * [Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue.ts)
- * [Stack](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/stack.ts)
- * [Stack Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/stack_queue.ts)
+ * Disjoint Set
+ * [Disjoint Set](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/disjoint_set/disjoint_set.ts)
+ * Test
+ * [Disjoint Set.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/disjoint_set/test/disjoint_set.test.ts)
+ * Heap
+ * [Heap](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/heap/heap.ts)
+ * Test
+ * [Max Heap.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/heap/test/max_heap.test.ts)
+ * [Min Heap.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/heap/test/min_heap.test.ts)
+ * List
+ * [Doubly Linked List](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/list/doubly_linked_list.ts)
+ * [Linked List](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/list/linked_list.ts)
+ * [Singly Linked List](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/list/singly_linked_list.ts)
+ * Test
+ * [Doubly Linked List.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/list/test/doubly_linked_list.test.ts)
+ * [Linked List](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/list/test/linked_list.ts)
+ * [Singly Linked List.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/list/test/singly_linked_list.test.ts)
+ * Map
+ * [Hash Map](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/map/hash_map.ts)
+ * [Map](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/map/map.ts)
+ * Test
+ * [Hash Map.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/map/test/hash_map.test.ts)
+ * Queue
+ * [Array Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/array_queue.ts)
+ * [Circular Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/circular_queue.ts)
+ * [Linked Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/linked_queue.ts)
+ * [Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/queue.ts)
+ * [Stack Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/stack_queue.ts)
+ * Test
+ * [Array Queue.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/test/array_queue.test.ts)
+ * [Circular Queue.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/test/circular_queue.test.ts)
+ * [Linked Queue.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/test/linked_queue.test.ts)
+ * [Queue](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/test/queue.ts)
+ * [Stack Queue.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/queue/test/stack_queue.test.ts)
+ * Set
+ * [Hash Map Set](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/set/hash_map_set.ts)
+ * [Map Set](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/set/map_set.ts)
+ * [Set](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/set/set.ts)
+ * Stack
+ * [Linked List Stack](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/stack/linked_list_stack.ts)
+ * [Stack](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/stack/stack.ts)
+ * Test
+ * [Linked List Stack.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/stack/test/linked_list_stack.test.ts)
+ * [Stack.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/stack/test/stack.test.ts)
+ * Tree
+ * [Binary Search Tree](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/tree/binary_search_tree.ts)
+ * Test
+ * [Binary Search Tree.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/data_structures/tree/test/binary_search_tree.test.ts)
 
 ## Dynamic Programming
  * [Knapsack](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/dynamic_programming/knapsack.ts)
 
+## Graph
+ * [Bellman Ford](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/graph/bellman_ford.ts)
+ * [Dijkstra](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/graph/dijkstra.ts)
+ * [Kruskal](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/graph/kruskal.ts)
+ * Test
+ * [Bellman Ford.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/graph/test/bellman_ford.test.ts)
+ * [Dijkstra.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/graph/test/dijkstra.test.ts)
+ * [Kruskal.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/graph/test/kruskal.test.ts)
+
 ## Maths
  * [Absolute Value](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/absolute_value.ts)
  * [Aliquot Sum](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/aliquot_sum.ts)
  * [Armstrong Number](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/armstrong_number.ts)
  * [Binary Convert](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/binary_convert.ts)
+ * [Binomial Coefficient](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/binomial_coefficient.ts)
  * [Calculate Mean](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/calculate_mean.ts)
+ * [Calculate Median](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/calculate_median.ts)
  * [Degrees To Radians](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/degrees_to_radians.ts)
  * [Digit Sum](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/digit_sum.ts)
  * [Factorial](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/factorial.ts)
+ * [Factors](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/factors.ts)
  * [Fibonacci](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/fibonacci.ts)
  * [Find Min](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/find_min.ts)
  * [Greatest Common Factor](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/greatest_common_factor.ts)
@@ -31,8 +86,13 @@
  * [Is Odd](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/is_odd.ts)
  * [Is Palindrome](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/is_palindrome.ts)
  * [Is Square Free](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/is_square_free.ts)
+ * [Juggler Sequence](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/juggler_sequence.ts)
  * [Lowest Common Multiple](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/lowest_common_multiple.ts)
+ * [Number Of Digits](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/number_of_digits.ts)
+ * [Pascals Triangle](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/pascals_triangle.ts)
+ * [Perfect Cube](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/perfect_cube.ts)
  * [Perfect Square](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/perfect_square.ts)
+ * [Primes](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/primes.ts)
  * [Pronic Number](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/pronic_number.ts)
  * [Radians To Degrees](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/radians_to_degrees.ts)
  * Series
@@ -41,6 +101,7 @@
  * [Hexagonal Numbers.Test](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/series/test/hexagonal_numbers.test.ts)
  * [Sieve Of Eratosthenes](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/sieve_of_eratosthenes.ts)
  * [Signum](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/signum.ts)
+ * [Zellers Congruence](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/zellers_congruence.ts)
 
 ## Other
  * [Parse Nested Brackets](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/other/parse_nested_brackets.ts)
@@ -58,4 +119,7 @@
  * [Gnome Sort](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/sorts/gnome_sort.ts)
  * [Insertion Sort](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/sorts/insertion_sort.ts)
  * [Merge Sort](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/sorts/merge_sort.ts)
+ * [Quick Select](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/sorts/quick_select.ts)
  * [Quick Sort](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/sorts/quick_sort.ts)
+ * [Selection Sort](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/sorts/selection_sort.ts)
+ * [Shell Sort](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/sorts/shell_sort.ts)

maths/primes.ts

@@ -0,0 +1,87 @@
+/**
+ * Implementation of the Sieve of Eratosthenes algorithm.
+ *
+ * @param limit An integer _n_ > 1
+ * @returns All prime numbers from 2 through {@link limit}
+ *
+ * @see https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
+ */
+export function sieveOfEratosthenes(limit: number): number[] {
+ if (!Number.isInteger(limit) || limit <= 1) {
+ throw new Error("limit should be an integer greater than 1");
+ }
+
+ const maybePrime: boolean[] = new Array(limit + 1).fill(true);
+ for (let i = 2; i * i <= limit; i++) {
+ if (!maybePrime[i]) continue;
+ for (let j = i * i; j <= limit; j += i) {
+ maybePrime[j] = false;
+ }
+ }
+
+ const primes: number[] = [];
+ for (let i = 2; i < maybePrime.length; i++) {
+ if (maybePrime[i]) {
+ primes.push(i);
+ }
+ }
+
+ return primes;
+}
+
+/**
+ * Generator that yields primes.
+ *
+ * Inspired by https://gist.github.com/e-nikolov/cd94db0de2a6b70da144124ae93a6458
+ */
+export function* primeGenerator() {
+ type NumberGen = Generator<number, void, any>;
+
+ function* filter(input: NumberGen, prime: number): NumberGen {
+ while (true) {
+ const {done, value} = input.next();
+ if (done) break;
+ if (value % prime !== 0) yield value;
+ }
+ }
+
+ let chain: NumberGen = (function* () {
+ let i = 2;
+ while (true) yield i++;
+ })();
+
+ while (true) {
+ const {done, value} = chain.next();
+ if (done) break;
+ yield value;
+ chain = filter(chain, value);
+ }
+}
+
+/**
+ * @function isPrime
+ * @description Determine if given number is prime.
+ * @param {number} num - A natural number.
+ * @return {boolean} - Whether the given number is prime.
+ * @see https://en.wikipedia.org/wiki/Prime_number
+ * @example isPrime(2) = false
+ * @example isPrime(3) = true
+ */
+export const isPrime = (num: number): boolean => {
+ // raise corresponding errors upon invalid inputs
+ if (num <= 0 || !Number.isInteger(num)) {
+ throw new Error("only natural numbers are supported");
+ }
+
+ // handle input being 1
+ if (num === 1) return false;
+
+ // iterate from 2 to the square root of num to find a factor
+ // return false upon finding a factor
+ for (let i = 2; i <= Math.sqrt(num); i++) {
+ if (num % i === 0) return false;
+ }
+
+ // if the entire loop runs without finding a factor, return true
+ return true;
+};

maths/test/primes.test.ts

@@ -0,0 +1,59 @@
+import {isPrime, primeGenerator, sieveOfEratosthenes} from "../primes";
+
+
+describe(sieveOfEratosthenes, () => {
+ test.each([-1, 0, 1, 2.123, 1337.80085])(
+ "should throw an error when given an invalid limit=%d",
+ (invalidLimit) => {
+ expect(() => sieveOfEratosthenes(invalidLimit)).toThrow();
+ }
+ );
+ test.each([
+ [2, [2]],
+ [3, [2, 3]],
+ [4, [2, 3]],
+ [5, [2, 3, 5]],
+ [6, [2, 3, 5]],
+ [7, [2, 3, 5, 7]],
+ [8, [2, 3, 5, 7]],
+ [9, [2, 3, 5, 7]],
+ ])(
+ "should return the expected list of primes for limit=%i",
+ (limit, expected) => {
+ expect(sieveOfEratosthenes(limit)).toEqual(expected);
+ }
+ );
+});
+
+describe(primeGenerator, () => {
+ it("should generate prime numbers", () => {
+ const primeGen = primeGenerator();
+ for (let i = 0; i < 100; i++) {
+ const prime = primeGen.next().value;
+
+ if (prime === undefined) {
+ throw new Error("prime generator returned undefined");
+ }
+
+ expect(isPrime(prime)).toBe(true);
+ }
+ });
+});
+
+describe("IsPrime", () => {
+ test.each([[1, false], [2, true], [3, true], [3 * 3, false], [13, true], [24, false]])(
+ "correct output for %i",
+ (nums, expected) => {
+ expect(isPrime(nums)).toBe(expected);
+ },
+ );
+
+ test.each([-890, -5.56, -7, 0.73, 4.2, NaN, -Infinity, Infinity])(
+ "should throw an error for non natural number %d",
+ (num) => {
+ expect(() => isPrime(num)).toThrowError(
+ "only natural numbers are supported",
+ );
+ },
+ );
+});