Add activity for Sieve of Eratosthenes

Author: jcazevedo

src/main/java/com/packt/datastructuresandalg/lesson7/activity/sieve/SieveOfEratosthenes.java

@@ -0,0 +1,11 @@
+package com.packt.datastructuresandalg.lesson7.activity.sieve;
+
+public class SieveOfEratosthenes {
+    public SieveOfEratosthenes(int maxValue) {
+        // Build the sieve here
+    }
+
+    public boolean isPrime(int value) {
+        return false;
+    }
+}

src/main/java/com/packt/datastructuresandalg/lesson7/activity/sieve/solution/SieveOfEratosthenes.java

@@ -0,0 +1,25 @@
+package com.packt.datastructuresandalg.lesson7.activity.sieve.solution;
+
+import java.util.Arrays;
+
+public class SieveOfEratosthenes {
+    private boolean[] prime;
+
+    public SieveOfEratosthenes(int maxValue) {
+        prime = new boolean[maxValue + 1];
+        Arrays.fill(prime, true);
+        prime[0] = prime[1] = false;
+        int l = (int) Math.sqrt(maxValue);
+        for (int i = 2; i <= l; i++) {
+            if (prime[i]) {
+                for (int j = i * i; j <= maxValue; j += i) {
+                    prime[j] = false;
+                }
+            }
+        }
+    }
+
+    public boolean isPrime(int value) {
+        return prime[value];
+    }
+}

src/test/java/com/packt/datastructuresandalg/lesson7/activity/sieve/SieveOfEratosthenesTest.java

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+package com.packt.datastructuresandalg.lesson7.activity.sieve;
+
+import junit.framework.TestCase;
+
+public class SieveOfEratosthenesTest extends TestCase {
+    SieveOfEratosthenes sieve = new SieveOfEratosthenes(1000000);
+
+    public void test0() {
+        assertFalse(sieve.isPrime(0));
+    }
+
+    public void test1() {
+        assertFalse(sieve.isPrime(1));
+    }
+
+    public void test2() {
+        assertTrue(sieve.isPrime(2));
+    }
+
+    public void test289049() {
+        assertTrue(sieve.isPrime(289049));
+    }
+
+    public void test690997() {
+        assertTrue(sieve.isPrime(690997));
+    }
+
+    public void test690998() {
+        assertFalse(sieve.isPrime(690998));
+    }
+
+    public void test999983() {
+        assertTrue(sieve.isPrime(999983));
+    }
+
+    public void test999999() {
+        assertFalse(sieve.isPrime(999999));
+    }
+}