update(array) : prime sieve of eratosthenes

Author: dhrubach

simple_array/e_primes_to_n.py

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+###################################################
+# LeetCode Problem Number : 204
+# Difficulty Level : Easy
+# URL : https://leetcode.com/problems/count-primes/
+###################################################
+
+
+from typing import List, Union
+
+
+class PrimeNumber:
+    def generate_primes(self, n: int) -> Union[int, List[int]]:
+        primes = []
+        is_prime = [False, False] + [True] * (n - 1)
+
+        for i in range(2, n + 1):
+            if is_prime[i]:
+                primes.append(i)
+
+                for j in range(i * i, n + 1, i):
+                    is_prime[j] = False
+
+        return [len(primes), primes]

simple_array/tests/e_primes_to_n_test.py

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+from simple_array.e_primes_to_n import PrimeNumber
+
+
+class TestPrimeNumber:
+    def test_generate_primes(self):
+        pn = PrimeNumber()
+
+        input = 10
+        result = pn.generate_primes(input)
+        assert result[0] == 4
+        assert result[1] == [2, 3, 5, 7]