Add Greedy Algorithms (fixes #4493) (#4504)

src/test/java/com/thealgorithms/greedyalgorithms/ActivitySelectionTest.java

@@ -0,0 +1,42 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+public class ActivitySelectionTest {
+    @Test
+    public void testActivitySelection() {
+        int start[] = {1, 3, 0, 5, 8, 5};
+        int end[] = {2, 4, 6, 7, 9, 9};
+
+        ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0, 1, 3, 4));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testSingleActivity() {
+        int start[] = {1};
+        int end[] = {2};
+
+        ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testNoOverlap() {
+        int start[] = {1, 2, 3};
+        int end[] = {2, 3, 4};
+
+        ArrayList<Integer> result = ActivitySelection.activitySelection(start, end);
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(0, 1, 2));
+
+        assertEquals(expected, result);
+    }
+}

src/test/java/com/thealgorithms/greedyalgorithms/CoinChangeTest.java

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+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+public class CoinChangeTest {
+    @Test
+    public void testCoinChangeProblemWithValidAmount() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(500, 50, 20, 20, 1));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(591);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithLargeAmount() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2000));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(2000);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithPartialCoins2() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(500, 50, 20));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(570);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithSmallAmount() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2, 1));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(3);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithLargeAmountAndMultipleDenominations() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2000, 2000, 2000, 2000, 500, 500, 500, 100, 100, 100, 100, 50, 20, 20, 5, 2, 2));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(9999);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithAllDenominations() {
+        ArrayList<Integer> expected = new ArrayList<>(Arrays.asList(2000, 500, 100, 100, 100, 50, 20, 10, 5, 2, 1));
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(2888);
+        assertEquals(expected, coins);
+    }
+
+    @Test
+    public void testCoinChangeProblemWithZeroAmount() {
+        ArrayList<Integer> expected = new ArrayList<>();
+        ArrayList<Integer> coins = CoinChange.coinChangeProblem(0);
+        assertEquals(expected, coins);
+    }
+}

src/test/java/com/thealgorithms/greedyalgorithms/FractionalKnapsackTest.java

@@ -0,0 +1,32 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class FractionalKnapsackTest {
+
+    @Test
+    public void testFractionalKnapsackWithExampleCase() {
+        int weight[] = {10, 20, 30};
+        int value[] = {60, 100, 120};
+        int capacity = 50;
+        assertEquals(240, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
+    }
+
+    @Test
+    public void testFractionalKnapsackWithZeroCapacity() {
+        int weight[] = {10, 20, 30};
+        int value[] = {60, 100, 120};
+        int capacity = 0;
+        assertEquals(0, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
+    }
+
+    @Test
+    public void testFractionalKnapsackWithEmptyItems() {
+        int weight[] = {};
+        int value[] = {};
+        int capacity = 50;
+        assertEquals(0, FractionalKnapsack.fractionalKnapsack(weight, value, capacity));
+    }
+}

src/test/java/com/thealgorithms/greedyalgorithms/JobSequencingTest.java

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+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import org.junit.jupiter.api.Test;
+
+public class JobSequencingTest {
+    @Test
+    public void testJobSequencingWithExampleCase() {
+        ArrayList<JobSequencing.Job> jobs = new ArrayList<>();
+        jobs.add(new JobSequencing.Job('a', 2, 100));
+        jobs.add(new JobSequencing.Job('b', 1, 19));
+        jobs.add(new JobSequencing.Job('c', 2, 27));
+        jobs.add(new JobSequencing.Job('d', 1, 25));
+        jobs.add(new JobSequencing.Job('e', 3, 15));
+        Collections.sort(jobs);
+        String jobSequence = JobSequencing.findJobSequence(jobs, jobs.size());
+
+        assertEquals("Job Sequence: c -> a -> e", jobSequence);
+    }
+}