From e09a3494e3f3b957b10402d9252a0bddec4cc908 Mon Sep 17 00:00:00 2001
From: Haidong Ji
Date: Wed, 26 Dec 2018 18:02:55 -0600
Subject: Knapsack maximize gold done!

It was a bit tricky translating algo in course slide to code, especially
regarding array indexing. I left a bit and walked the dogs. After I came
back, my mind was clearer than before. Debugging after that solved the
problem!---
 .../sources/Knapsack.java                          | 41 ++++++++++++++++++++++
 .../tests/KnapsackTest.java                        | 14 ++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 AlgoDesignAndTechniqueEdxJava/sources/Knapsack.java
 create mode 100644 AlgoDesignAndTechniqueEdxJava/tests/KnapsackTest.java

diff --git a/AlgoDesignAndTechniqueEdxJava/sources/Knapsack.java b/AlgoDesignAndTechniqueEdxJava/sources/Knapsack.java
new file mode 100644
index 0000000..97e89aa
--- /dev/null
+++ b/AlgoDesignAndTechniqueEdxJava/sources/Knapsack.java
@@ -0,0 +1,41 @@
+import java.util.Scanner;
+
+public class Knapsack {
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        int W, n;
+        W = scanner.nextInt();
+        n = scanner.nextInt();
+        int[] w = new int[n];
+        for (int i = 0; i < n; i++) {
+            w[i] = scanner.nextInt();
+        }
+        System.out.println(optimalWeight(W, w));
+    }
+
+    public static int optimalWeight(int W, int[] w2) {
+        int j = w2.length;
+        int[][] value = new int[W + 1][j + 1];
+
+        for (int i = 0; i < j + 1; i++) {
+            for (int w = 0; w < W + 1; w++) {
+                if (i == 0 || w == 0) {
+                    value[w][i] = 0;
+                    continue;
+                }
+                value[w][i] = value[w][i - 1];
+                if (w2[i - 1] <= w) {
+                    int val = value[w - w2[i - 1]][i - 1] + w2[i - 1];
+                    if (value[w][i] < val) {
+                        value[w][i] = val;
+                    }
+                }
+            }
+
+        }
+
+        return value[W][j];
+    }
+
+}
diff --git a/AlgoDesignAndTechniqueEdxJava/tests/KnapsackTest.java b/AlgoDesignAndTechniqueEdxJava/tests/KnapsackTest.java
new file mode 100644
index 0000000..86624c7
--- /dev/null
+++ b/AlgoDesignAndTechniqueEdxJava/tests/KnapsackTest.java
@@ -0,0 +1,14 @@
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class KnapsackTest {
+
+    @Test
+    void test() {
+        int[] w = { 1, 4, 8 };
+        int W = 10;
+        assertEquals(9, Knapsack.optimalWeight(W, w));
+    }
+
+}
-- 
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