diff options
| -rw-r--r-- | AlgoDesignAndTechniqueEdxJava/sources/LargestNumber.java | 45 | ||||
| -rw-r--r-- | AlgoDesignAndTechniqueEdxJava/tests/LargestNumberTest.java | 10 |
2 files changed, 35 insertions, 20 deletions
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")); + } } |