fork download 
  1.     import java.util.ArrayList;
  2.     import java.util.Arrays;
  3.     import java.util.Iterator;
  4.     import java.util.List;
  5.     import java.util.Set;
  6.     import java.util.function.Function;
  7.     import java.util.stream.Collectors;
  8.     class CommonCharacters {
  9.       @SuppressWarnings("boxing")
  10.       private static String commonCharactersOf(String string1, String string2) {
  11.         // Requirement
  12.         //
  13.         // Always return lowercase versions of common characters. e.g.:
  14.         //
  15.         // OK: (a, a) -> a
  16.         // OK: (a, A) -> a
  17.         // OK: (A, A) -> a
  18.         // No: (A, A) -> A
  19.         // No: (aA, aA) -> aA
  20.         //
  21.         // Requirement
  22.         //
  23.         // Return common characters joined in a String, preserving the order in
  24.         // which they appeared in the longest argument, or in the first argument if
  25.         // the arguments are of the same length.
  26.         //
  27.         // Requirement
  28.         //
  29.         // Handle "characters" (i.e. code points) outside the Basic Multilingual
  30.         // Plane (BMP), including characters from Supplementary Planes.
  31.         // There should be no `char' or `Character' based "false positives". i.e.:
  32.         //
  33.         // String string1 = "\uD835\uDC00", string2 = "\uD835\uDC01";
  34.         //
  35.         // string1 and string2 share no characters in the intended acceptation of
  36.         // "character".
  37.         String shortestArgument, longestArgument;
  38.         if (string1.length() < string2.length()) {
  39.           shortestArgument = string1;
  40.           longestArgument = string2;
  41.         } else {
  42.           shortestArgument = string2;
  43.           longestArgument = string1;
  44.         }
  45.         // @formatter:off
  46.         Set<Integer> codePointsSeen =
  47.             shortestArgument.codePoints()
  48.             .boxed()
  49.             .map(Character::toLowerCase)
  50.             .collect(Collectors.toSet());
  51.         List<Integer> codePointsInCommon = new ArrayList<>();
  52.         for (Iterator<Integer> iterator = longestArgument.codePoints()
  53.                                                          .distinct()
  54.                                                          .iterator();
  55.              iterator.hasNext() &&
  56.              codePointsInCommon.size() < codePointsSeen.size();) {
  57.         // @formatter:on
  58.           Integer codePoint = iterator.next();
  59.           int lowerCaseCodePoint = Character.toLowerCase(codePoint);
  60.           if (codePointsSeen.contains(lowerCaseCodePoint)) {
  61.             codePointsInCommon.add(lowerCaseCodePoint);
  62.           }
  63.         }
  64.         StringBuilder stringBuilder = new StringBuilder();
  65.         for (Integer codePoint : codePointsInCommon) {
  66.           stringBuilder.appendCodePoint(codePoint);
  67.         }
  68.         return stringBuilder.toString();
  69.       }
  70.       @SuppressWarnings("boxing")
  71.       public static void main(String[] args) {
  72.         // @formatter:off
  73.         String[][] testArgumentsAndExpectedValues = {
  74.             { ""                     , ""                  , ""             },
  75.             { "a"                    , ""                  , ""             },
  76.             { ""                     , "a"                 , ""             },
  77.             { "aa"                   , ""                  , ""             },
  78.             { ""                     , "aa"                , ""             },
  79.             { "a"                    , "a"                 , "a"            },
  80.             { "aa"                   , "b"                 , ""             },
  81.             { "b"                    , "aa"                , ""             },
  82.             { "ab"                   , "ba"                , "ab"           },
  83.             { "aba"                  , "ab"                , "ab"           },
  84.             { "aba"                  , "ba"                , "ab"           },
  85.             { "aba"                  , "aab"               , "ab"           },
  86.             { "a"                    , "A"                 , "a"            },
  87.             { "A"                    , "a"                 , "a"            },
  88.             { "A"                    , "A"                 , "a"            },
  89.             { "ab"                   , "AB"                , "ab"           },
  90.             { "AB"                   , "ab"                , "ab"           },
  91.             { "aB"                   , "Ab"                , "ab"           },
  92.             { "aB"                   , "Ba"                , "ab"           },
  93.             { "aB"                   , "Ba"                , "ab"           },
  94.             { "a"                    , "\uD835\uDC1A"      , ""             },
  95.             { "\uD835\uDC1A"         , "\uD835\uDC1A"      , "\uD835\uDC1A" },
  96.             { "\uD835\uDC00"         , "\uD835\uDC00"      , "\uD835\uDC00" },
  97.             { "\uD835\uDC1A"         , "\uD835\uDC00"      , ""             },
  98.             { "\uD835\uDC00"         , "\uD835\uDC01"      , ""             },
  99.             { "\uD801\uDC2B"         , "\uD801\uDC2B"      , "\uD801\uDC2B" },
  100.             { "\uD801\uDC03"         , "\uD801\uDC03"      , "\uD801\uDC2B" },
  101.             { "\uD801\uDC2B"         , "\uD801\uDC03"      , "\uD801\uDC2B" },
  102.             { "\uD83D\uDE80"         , "\uD83D\uDE80"      , "\uD83D\uDE80" },
  103.             { "a"                    , "aaaaaaaaaaaaaaaaa" , "a"            },
  104.             // The last test should still work, and work fast, with a second
  105.             // argument string starting with "a" and ending _many_ characters later
  106.             // The last test values doe not test it, but illustrate the scenario
  107.         };
  108.         int maximumTestArgumentLength =
  109.             Arrays.stream(testArgumentsAndExpectedValues)
  110.                   .flatMap(testValues -> Arrays.stream(testValues)
  111.                                                .limit(2))
  112.                   .mapToInt(String::length)
  113.                   .max()
  114.                   .getAsInt();
  115.         // @formatter:on
  116.         int maximumQuotedTestArgumentLength = maximumTestArgumentLength + 2;
  117.         for (int i = 0; i < testArgumentsAndExpectedValues.length; i++) {
  118.           String[] currentTestValues = testArgumentsAndExpectedValues[i];
  119.           String string1 = currentTestValues[0];
  120.           String string2 = currentTestValues[1];
  121.           String expectedResult = currentTestValues[2];
  122.           String actualResult = commonCharactersOf(string1, string2);
  123.           boolean testSuccessful = expectedResult.equals(actualResult);
  124.           if (testSuccessful) {
  125.             // continue; // TODO: uncomment to filter out successful tests
  126.           }
  127.           Function<String, String> quoteString = s -> '"' + s + '"';
  128.           // @formatter:off
  129.           String outputFormat = "%2d) "
  130.                               + "%5s: "
  131.                               + "(%-" + maximumQuotedTestArgumentLength + "s"
  132.                               + " , "
  133.                               + "%-" + maximumQuotedTestArgumentLength + "s)"
  134.                               + " -> "
  135.                               + "%s "
  136.                               + "(%s)"
  137.                               + "%n";
  138.           System.out.printf(outputFormat,
  139.                             i,
  140.                             testSuccessful ? "Success" : "Failure",
  141.                             quoteString.apply(string1),
  142.                             quoteString.apply(string2),
  143.                             quoteString.apply(actualResult),
  144.                             quoteString.apply(expectedResult));
  145.           // @formatter:on
  146.         }
  147.       }
  148.     }
  149.  
  150.  
Success #stdin #stdout 0.25s 321152KB
comments (?)
stdin 
Standard input is empty
stdout 
 0) Success: (""                  , ""                 ) -> "" ("")
 1) Success: ("a"                 , ""                 ) -> "" ("")
 2) Success: (""                  , "a"                ) -> "" ("")
 3) Success: ("aa"                , ""                 ) -> "" ("")
 4) Success: (""                  , "aa"               ) -> "" ("")
 5) Success: ("a"                 , "a"                ) -> "a" ("a")
 6) Success: ("aa"                , "b"                ) -> "" ("")
 7) Success: ("b"                 , "aa"               ) -> "" ("")
 8) Success: ("ab"                , "ba"               ) -> "ab" ("ab")
 9) Success: ("aba"               , "ab"               ) -> "ab" ("ab")
10) Success: ("aba"               , "ba"               ) -> "ab" ("ab")
11) Success: ("aba"               , "aab"              ) -> "ab" ("ab")
12) Success: ("a"                 , "A"                ) -> "a" ("a")
13) Success: ("A"                 , "a"                ) -> "a" ("a")
14) Success: ("A"                 , "A"                ) -> "a" ("a")
15) Success: ("ab"                , "AB"               ) -> "ab" ("ab")
16) Success: ("AB"                , "ab"               ) -> "ab" ("ab")
17) Success: ("aB"                , "Ab"               ) -> "ab" ("ab")
18) Success: ("aB"                , "Ba"               ) -> "ab" ("ab")
19) Success: ("aB"                , "Ba"               ) -> "ab" ("ab")
20) Success: ("a"                 , "𝐚"               ) -> "" ("")
21) Success: ("𝐚"                , "𝐚"               ) -> "𝐚" ("𝐚")
22) Success: ("𝐀"                , "𝐀"               ) -> "𝐀" ("𝐀")
23) Success: ("𝐚"                , "𝐀"               ) -> "" ("")
24) Success: ("𝐀"                , "𝐁"               ) -> "" ("")
25) Success: ("𐐫"                , "𐐫"               ) -> "𐐫" ("𐐫")
26) Success: ("𐐃"                , "𐐃"               ) -> "𐐫" ("𐐫")
27) Success: ("𐐫"                , "𐐃"               ) -> "𐐫" ("𐐫")
28) Success: ("🚀"                , "🚀"               ) -> "🚀" ("🚀")
29) Success: ("a"                 , "aaaaaaaaaaaaaaaaa") -> "a" ("a")
https://ideone.com/nqc3Qo
language:
Java (HotSpot 12)
created:
10 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!