From eb3a6e192072e9ddb82c5a9cf283196558d61e45 Mon Sep 17 00:00:00 2001
From: Haidong Ji
Date: Mon, 6 Aug 2018 22:15:40 -0500
Subject: Maximum Pairwise Product done!

---
 .../sources/MaxPairProduct.java                    |  59 ++++++++++++
 .../tests/MaxPairProductTest.java                  | 103 +++++++++++++++++++++
 2 files changed, 162 insertions(+)
 create mode 100644 AlgoDesignAndTechniqueEdxJava/sources/MaxPairProduct.java
 create mode 100644 AlgoDesignAndTechniqueEdxJava/tests/MaxPairProductTest.java

(limited to 'AlgoDesignAndTechniqueEdxJava')

diff --git a/AlgoDesignAndTechniqueEdxJava/sources/MaxPairProduct.java b/AlgoDesignAndTechniqueEdxJava/sources/MaxPairProduct.java
new file mode 100644
index 0000000..18b9521
--- /dev/null
+++ b/AlgoDesignAndTechniqueEdxJava/sources/MaxPairProduct.java
@@ -0,0 +1,59 @@
+import java.util.Scanner;
+
+public class MaxPairProduct {
+	int numberOfIntegers;
+	int biggest;
+	int bigger;
+
+	public MaxPairProduct(int size) {
+		numberOfIntegers = size;
+	}
+
+	public int getCount() {
+		return numberOfIntegers;
+	}
+
+	public static void main(String[] args) {
+		Scanner s = new Scanner(System.in);
+		
+		int n = s.nextInt();
+		MaxPairProduct mpp = new MaxPairProduct(n);
+		for (int i = 0; i<n; i++) {
+			mpp.newNumber(s.nextInt());
+		}
+		
+		s.close();
+		
+		System.out.println(mpp.getProduct());
+
+	}
+
+	public int getBiggest() {
+		return biggest;
+	}
+
+	public int getBigger() {
+		return bigger;
+	}
+
+	public void newNumber(int i) {
+		if (i > biggest) {
+			bigger = biggest;
+			biggest = i;
+		} else if (i == biggest) {
+			bigger = i;
+		} else if (i > bigger) {
+			bigger = i;
+		}
+	}
+
+	public long getProduct() {
+		if (numberOfIntegers == 0) {
+			return (long) 0;
+		} else if (numberOfIntegers == 1) {
+			return (long) biggest;
+		}
+		return (long) biggest * (long) bigger;
+	}
+
+}
diff --git a/AlgoDesignAndTechniqueEdxJava/tests/MaxPairProductTest.java b/AlgoDesignAndTechniqueEdxJava/tests/MaxPairProductTest.java
new file mode 100644
index 0000000..7f0b313
--- /dev/null
+++ b/AlgoDesignAndTechniqueEdxJava/tests/MaxPairProductTest.java
@@ -0,0 +1,103 @@
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class MaxPairProductTest {
+
+	@Test
+	void testMaxPairProductSize() {
+		MaxPairProduct mpp = new MaxPairProduct(5);
+		assertEquals(5, mpp.getCount());
+	}
+
+	@Test
+	void testMaxPairProductBiggest0() {
+		MaxPairProduct mpp = new MaxPairProduct(1);
+		assertEquals(0, mpp.getBiggest());
+	}
+
+	@Test
+	void testMaxPairProductBigger0() {
+		MaxPairProduct mpp = new MaxPairProduct(1);
+		assertEquals(0, mpp.getBigger());
+	}
+
+	@Test
+	void testMaxPairProductNewNumber1() {
+		MaxPairProduct mpp = new MaxPairProduct(1);
+		mpp.newNumber(1);
+		assertEquals(0, mpp.getBigger());
+		assertEquals(1, mpp.getBiggest());
+		assertEquals(1, mpp.getProduct());
+	}
+
+	@Test
+	void testMaxPairProductNewNumber2() {
+		MaxPairProduct mpp = new MaxPairProduct(2);
+		mpp.newNumber(1);
+		mpp.newNumber(1);
+		assertEquals(1, mpp.getBigger());
+		assertEquals(1, mpp.getBiggest());
+		assertEquals(1, mpp.getProduct());
+	}
+
+	@Test
+	void testMaxPairProductNewNumber2_1() {
+		MaxPairProduct mpp = new MaxPairProduct(2);
+		mpp.newNumber(1);
+		mpp.newNumber(2);
+		assertEquals(1, mpp.getBigger());
+		assertEquals(2, mpp.getBiggest());
+		assertEquals(2, mpp.getProduct());
+	}
+
+	@Test
+	void testMaxPairProductNewNumber3() {
+		MaxPairProduct mpp = new MaxPairProduct(3);
+		mpp.newNumber(1);
+		mpp.newNumber(2);
+		mpp.newNumber(2);
+		assertEquals(2, mpp.getBigger());
+		assertEquals(2, mpp.getBiggest());
+		assertEquals(4, mpp.getProduct());
+	}
+
+	@Test
+	void testMaxPairProductNewNumber3_1() {
+		MaxPairProduct mpp = new MaxPairProduct(3);
+		mpp.newNumber(1);
+		mpp.newNumber(2);
+		mpp.newNumber(3);
+		assertEquals(2, mpp.getBigger());
+		assertEquals(3, mpp.getBiggest());
+		assertEquals(6, mpp.getProduct());
+	}
+
+	@Test
+	void testMaxPairProductNewNumber10() {
+		MaxPairProduct mpp = new MaxPairProduct(10);
+		mpp.newNumber(7);
+		mpp.newNumber(5);
+		mpp.newNumber(14);
+		mpp.newNumber(2);
+		mpp.newNumber(8);
+		mpp.newNumber(8);
+		mpp.newNumber(10);
+		mpp.newNumber(1);
+		mpp.newNumber(2);
+		mpp.newNumber(3);
+		assertEquals(140, mpp.getProduct());
+	}
+
+	@Test
+	void testMaxPairProductNewNumber2_2() {
+		MaxPairProduct mpp = new MaxPairProduct(2);
+		mpp.newNumber(100000);
+		mpp.newNumber(90000);
+		assertEquals(90000, mpp.getBigger());
+		assertEquals(100000, mpp.getBiggest());
+		assertEquals(9000000000L, mpp.getProduct());
+	}
+
+}
-- 
cgit v1.2.3