Feat(Improved): Add 0/1 Knapsack Problem: Recursive and Tabulation (Bottom-Up DP) Implementations in Java along with their corresponding Tests (#6425)

* feat: Add 0/1 Knapsack and its tabulation implementation with their corresponding tests * feat: Add 0/1 Knapsack and its tabulation implementation with their corresponding tests * feat: Add 0/1 Knapsack and its tabulation implementation with their corresponding tests * Feat:add 0/1knapsack and 0/1knapsacktabulation along with their tests * Feat:add 0/1knapsack and 0/1knapsacktabulation along with their tests * Feat:add 0/1knapsack and 0/1knapsacktabulation along with their tests --------- Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
2025-12-19 07:00:35 +08:00 · 2025-07-22 22:47:24 +05:30
parent bbbc1dd946
commit cfd784105b
4 changed files with 268 additions and 0 deletions
--- a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulationTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTabulationTest.java
@@ -0,0 +1,78 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class KnapsackZeroOneTabulationTest {
+
+    @Test
+    public void basicCheck() {
+        int[] values = {60, 100, 120};
+        int[] weights = {10, 20, 30};
+        int capacity = 50;
+        int itemCount = values.length;
+
+        int expected = 220; // Best choice: item 1 (100) and item 2 (120)
+        int result = KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void emptyKnapsack() {
+        int[] values = {};
+        int[] weights = {};
+        int capacity = 50;
+        int itemCount = 0;
+
+        assertEquals(0, KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount));
+    }
+
+    @Test
+    public void zeroCapacity() {
+        int[] values = {60, 100, 120};
+        int[] weights = {10, 20, 30};
+        int capacity = 0;
+        int itemCount = values.length;
+
+        assertEquals(0, KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount));
+    }
+
+    @Test
+    public void negativeCapacity() {
+        int[] values = {10, 20, 30};
+        int[] weights = {1, 1, 1};
+        int capacity = -10;
+        int itemCount = values.length;
+
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount));
+        assertEquals("Capacity must not be negative.", exception.getMessage());
+    }
+
+    @Test
+    public void mismatchedLengths() {
+        int[] values = {60, 100}; // Only 2 values
+        int[] weights = {10, 20, 30}; // 3 weights
+        int capacity = 50;
+        int itemCount = 2; // Matches `values.length`
+
+        // You could either expect 0 or throw an IllegalArgumentException in your compute function
+        assertThrows(IllegalArgumentException.class, () -> { KnapsackZeroOneTabulation.compute(values, weights, capacity, itemCount); });
+    }
+
+    @Test
+    public void nullInputs() {
+        int[] weights = {1, 2, 3};
+        int capacity = 10;
+        int itemCount = 3;
+
+        IllegalArgumentException exception1 = assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOneTabulation.compute(null, weights, capacity, itemCount));
+        assertEquals("Values and weights arrays must not be null.", exception1.getMessage());
+
+        int[] values = {1, 2, 3};
+
+        IllegalArgumentException exception2 = assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOneTabulation.compute(values, null, capacity, itemCount));
+        assertEquals("Values and weights arrays must not be null.", exception2.getMessage());
+    }
+}
--- a/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTest.java
+++ b/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackZeroOneTest.java
@@ -0,0 +1,68 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class KnapsackZeroOneTest {
+
+    @Test
+    void basicCheck() {
+        int[] values = {60, 100, 120};
+        int[] weights = {10, 20, 30};
+        int capacity = 50;
+        int expected = 220;
+
+        int result = KnapsackZeroOne.compute(values, weights, capacity, values.length);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void zeroCapacity() {
+        int[] values = {10, 20, 30};
+        int[] weights = {1, 1, 1};
+        int capacity = 0;
+
+        int result = KnapsackZeroOne.compute(values, weights, capacity, values.length);
+        assertEquals(0, result);
+    }
+
+    @Test
+    void zeroItems() {
+        int[] values = {};
+        int[] weights = {};
+        int capacity = 10;
+
+        int result = KnapsackZeroOne.compute(values, weights, capacity, 0);
+        assertEquals(0, result);
+    }
+
+    @Test
+    void weightsExceedingCapacity() {
+        int[] values = {10, 20};
+        int[] weights = {100, 200};
+        int capacity = 50;
+
+        int result = KnapsackZeroOne.compute(values, weights, capacity, values.length);
+        assertEquals(0, result);
+    }
+
+    @Test
+    void throwsOnNullArrays() {
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(null, new int[] {1}, 10, 1));
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(new int[] {1}, null, 10, 1));
+    }
+
+    @Test
+    void throwsOnMismatchedArrayLengths() {
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(new int[] {10, 20}, new int[] {5}, 15, 2));
+    }
+
+    @Test
+    void throwsOnNegativeInputs() {
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(new int[] {10}, new int[] {5}, -1, 1));
+
+        assertThrows(IllegalArgumentException.class, () -> KnapsackZeroOne.compute(new int[] {10}, new int[] {5}, 5, -1));
+    }
+}