From aa32f7835fa2776e29fb42c3bdac06ab1f489d0f Mon Sep 17 00:00:00 2001
From: Haidong Ji
Date: Fri, 7 Sep 2018 20:59:25 -0500
Subject: Max Dot Product done.

I wasn't just a little surprised how simple it is.---
 .../sources/MaxDotProd.java                        | 30 ++++++++++++++++++++++
 .../tests/MaxDotProdTest.java                      | 28 ++++++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 AlgoDesignAndTechniqueEdxJava/sources/MaxDotProd.java
 create mode 100644 AlgoDesignAndTechniqueEdxJava/tests/MaxDotProdTest.java

diff --git a/AlgoDesignAndTechniqueEdxJava/sources/MaxDotProd.java b/AlgoDesignAndTechniqueEdxJava/sources/MaxDotProd.java
new file mode 100644
index 0000000..77672aa
--- /dev/null
+++ b/AlgoDesignAndTechniqueEdxJava/sources/MaxDotProd.java
@@ -0,0 +1,30 @@
+import java.util.Arrays;
+import java.util.Scanner;
+
+public class MaxDotProd {
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        int n = scanner.nextInt();
+        int[] a = new int[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = scanner.nextInt();
+        }
+        int[] b = new int[n];
+        for (int i = 0; i < n; i++) {
+            b[i] = scanner.nextInt();
+        }
+        System.out.println(getMaxDotProduct(a, b));
+    }
+
+	public static long getMaxDotProduct(int[] a, int[] b) {
+		Arrays.sort(a);
+		Arrays.sort(b);
+		long result = 0;
+		for (int i = 0; i < b.length; i++) {
+			result = (long) a[i] * b[i] + result;
+		}
+		return result;
+	}
+
+}
diff --git a/AlgoDesignAndTechniqueEdxJava/tests/MaxDotProdTest.java b/AlgoDesignAndTechniqueEdxJava/tests/MaxDotProdTest.java
new file mode 100644
index 0000000..888967b
--- /dev/null
+++ b/AlgoDesignAndTechniqueEdxJava/tests/MaxDotProdTest.java
@@ -0,0 +1,28 @@
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class MaxDotProdTest {
+
+	@Test
+	void test() {
+		int[] a = new int[] { 60, 100, 120 };
+		int[] b = new int[] { 20, 50, 30 };
+		assertEquals(10200, MaxDotProd.getMaxDotProduct(a, b));
+	}
+
+	@Test
+	void test1() {
+		int[] a = new int[] { 23};
+		int[] b = new int[] { 39 };
+		assertEquals(897, MaxDotProd.getMaxDotProduct(a, b));
+	}
+
+	@Test
+	void test2() {
+		int[] a = new int[] { 1,3,-5};
+		int[] b = new int[] { -2,4,1 };
+		assertEquals(23, MaxDotProd.getMaxDotProduct(a, b));
+	}
+
+}
-- 
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