Add ProportionalFairScheduling algorithm (#5812)

Author: Hardvan

DIRECTORY.md

@@ -538,6 +538,7 @@
             * [MultiAgentScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MultiAgentScheduling.java)
             * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
+            * [ProportionalFairScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
             * [SelfAdjustingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java)
             * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java)
@@ -1136,6 +1137,7 @@
             * [MultiAgentSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MultiAgentSchedulingTest.java)
             * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
+            * [ProportionalFairSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)
             * [SelfAdjustingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java)
             * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java)

src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java

@@ -0,0 +1,54 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * ProportionalFairScheduling allocates resources to processes based on their
+ * proportional weight or importance. It aims to balance fairness with
+ * priority, ensuring that higher-weight processes receive a larger share of resources.
+ *
+ * Use Case: Network bandwidth allocation in cellular networks (4G/5G),
+ * where devices receive a proportional share of bandwidth.
+ *
+ * @author Hardvan
+ */
+public final class ProportionalFairScheduling {
+
+    static class Process {
+        String name;
+        int weight;
+        int allocatedResources;
+
+        Process(String name, int weight) {
+            this.name = name;
+            this.weight = weight;
+            this.allocatedResources = 0;
+        }
+    }
+
+    private final List<Process> processes;
+
+    public ProportionalFairScheduling() {
+        processes = new ArrayList<>();
+    }
+
+    public void addProcess(String name, int weight) {
+        processes.add(new Process(name, weight));
+    }
+
+    public void allocateResources(int totalResources) {
+        int totalWeight = processes.stream().mapToInt(p -> p.weight).sum();
+        for (Process process : processes) {
+            process.allocatedResources = (int) ((double) process.weight / totalWeight * totalResources);
+        }
+    }
+
+    public List<String> getAllocatedResources() {
+        List<String> allocation = new ArrayList<>();
+        for (Process process : processes) {
+            allocation.add(process.name + ": " + process.allocatedResources);
+        }
+        return allocation;
+    }
+}

src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java

@@ -0,0 +1,53 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class ProportionalFairSchedulingTest {
+
+    private ProportionalFairScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new ProportionalFairScheduling();
+    }
+
+    @Test
+    public void testAllocateResourcesSingleProcess() {
+        scheduler.addProcess("Process1", 5);
+        scheduler.allocateResources(100);
+        List<String> expected = List.of("Process1: 100");
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesMultipleProcesses() {
+        scheduler.addProcess("Process1", 2);
+        scheduler.addProcess("Process2", 3);
+        scheduler.addProcess("Process3", 5);
+        scheduler.allocateResources(100);
+        List<String> expected = List.of("Process1: 20", "Process2: 30", "Process3: 50");
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesZeroWeightProcess() {
+        scheduler.addProcess("Process1", 0);
+        scheduler.addProcess("Process2", 5);
+        scheduler.allocateResources(100);
+        List<String> expected = List.of("Process1: 0", "Process2: 100");
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+
+    @Test
+    public void testAllocateResourcesEqualWeights() {
+        scheduler.addProcess("Process1", 1);
+        scheduler.addProcess("Process2", 1);
+        scheduler.allocateResources(100);
+        List<String> expected = List.of("Process1: 50", "Process2: 50");
+        assertEquals(expected, scheduler.getAllocatedResources());
+    }
+}