From 109ade52e695184b54c68ff5426a8672d7443047 Mon Sep 17 00:00:00 2001
From: Haidong Ji
Date: Tue, 2 Oct 2018 21:46:45 -0500
Subject: Maximize salary done!

The compare algorithm provided by bytwigorlimerick was so clever and
elegant! https://courses.edx.org/courses/course-v1:UCSanDiegoX+ALGS200x+2T2017/discussion/forum/course/threads/5a427dbf44a15008cd000701---
 .../sources/LargestNumber.java                     | 45 ++++++++++++----------
 .../tests/LargestNumberTest.java                   | 10 +++++
 2 files changed, 35 insertions(+), 20 deletions(-)

(limited to 'AlgoDesignAndTechniqueEdxJava')

diff --git a/AlgoDesignAndTechniqueEdxJava/sources/LargestNumber.java b/AlgoDesignAndTechniqueEdxJava/sources/LargestNumber.java
index 0458b91..1ddff1e 100644
--- a/AlgoDesignAndTechniqueEdxJava/sources/LargestNumber.java
+++ b/AlgoDesignAndTechniqueEdxJava/sources/LargestNumber.java
@@ -34,26 +34,31 @@ public class LargestNumber {
 		return result;
 	}
 
-	public static boolean compareLeadingDigit(String string, String maxDigit) {
-		if (string.length() == maxDigit.length())
-			return Integer.parseInt(string) > Integer.parseInt(maxDigit);
-		if (string.length() < maxDigit.length()) {
-			if (string.charAt(0) > maxDigit.charAt(0)) {
-				return true;
-			} else if (string.charAt(0) < maxDigit.charAt(0)) {
-				return false;
-			} else if (string.charAt(0) > maxDigit.charAt(1)) {
-				return true;
-			} else if (string.charAt(0) < maxDigit.charAt(1)) {
-				return false;
-			} else if (maxDigit.length() == 2)
-				return false;
-			else {
-				return string.charAt(0) > maxDigit.charAt(2);
-			}
-		} else {
-			return !compareLeadingDigit(maxDigit, string);
-		}
+	public static boolean compareLeadingDigit(String s, String maxDigit) {
+//Oh my god, the algorithm for this comparison was so clever mentioned 
+//by bytwigorlimerick in this page:
+//https://courses.edx.org/courses/course-v1:UCSanDiegoX+ALGS200x+2T2017/discussion/forum/course/threads/5a427dbf44a15008cd000701
+//This solved the problem nicely and easily, so elegant!
+		return Integer.parseInt(s + maxDigit) > Integer.parseInt(maxDigit + s);
+//		if (s.length() == maxDigit.length())
+//			return Integer.parseInt(s) > Integer.parseInt(maxDigit);
+//		if (s.length() < maxDigit.length()) {
+//			if (s.charAt(0) > maxDigit.charAt(0)) {
+//				return true;
+//			} else if (s.charAt(0) < maxDigit.charAt(0)) {
+//				return false;
+//			} else if (s.charAt(0) > maxDigit.charAt(1)) {
+//				return true;
+//			} else if (s.length() == 1) {
+//				if (s.charAt(0) > maxDigit.charAt(1))
+//					return true;
+//				else
+//					return false;
+//			} else
+//				return compareLeadingDigit(s.substring(1), maxDigit.substring(1));
+//		} else {
+//			return !compareLeadingDigit(maxDigit, s);
+//		}
 	}
 
 }
diff --git a/AlgoDesignAndTechniqueEdxJava/tests/LargestNumberTest.java b/AlgoDesignAndTechniqueEdxJava/tests/LargestNumberTest.java
index 285d502..4d62c6b 100644
--- a/AlgoDesignAndTechniqueEdxJava/tests/LargestNumberTest.java
+++ b/AlgoDesignAndTechniqueEdxJava/tests/LargestNumberTest.java
@@ -68,5 +68,15 @@ class LargestNumberTest {
 	void testCompareLeadingDigit6() {
 		assertTrue(LargestNumber.compareLeadingDigit("23", "2"));
 	}
+
+	@Test
+	void testCompareLeadingDigit7() {
+		assertTrue(LargestNumber.compareLeadingDigit("545", "54"));
+	}
+
+	@Test
+	void testCompareLeadingDigit8() {
+		assertTrue(LargestNumber.compareLeadingDigit("56", "565"));
+	}
 	
 }
-- 
cgit v1.2.3