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  1. import java.util.regex.*;
  2. import java.util.ArrayList;
  3.  
  4. public class Main {
  5.     private static Pattern combineRe(Pattern p1, Pattern p2){
  6.         return Pattern.compile(combineRE(p1.pattern(), p2.pattern()));
  7.     }
  8.     private static String combineRE(String p1, String p2){
  9.         return combineRE(p1, p2, true);
  10.     }
  11.     private static String combineRE(String p1, String p2, boolean anchors){
  12.         int groups1 = 0, groups2=0;
  13.         StringBuilder newP = new StringBuilder((anchors)?"^(?=":"(?=");
  14.         newP.append(p1);
  15.         if (anchors) newP.append('$');
  16.         newP.append(")(?=");
  17.  
  18.         Pattern capturingGroup = Pattern.compile("(?<!\\\\)(\\\\\\\\)*\\((?!\\?)");
  19.         Matcher m = capturingGroup.matcher(p1);
  20.         while(m.find()) groups1 ++;
  21.  
  22.         m = capturingGroup.matcher(p2);
  23.  
  24.         while(m.find()) groups2 ++;
  25.         String new2 = p2;
  26.  
  27.         for(int i=1; i<=groups2; i++)
  28.             new2 = new2.replaceAll("(?<!\\\\)\\\\"+i, "\\\\" + (i+groups1));
  29.  
  30.         newP.append(new2);
  31.         if (anchors) newP.append('$');
  32.         newP.append(')');
  33.         if (anchors) newP.append(".*");
  34.         return newP.toString();
  35.     }
  36.     private static String[] findAllCombinedRE(String p1, String p2, String haystack, boolean overlap){
  37.         ArrayList<String> toReturn = new ArrayList<String>();
  38.         Pattern pCombo = Pattern.compile(combineRE(p1,p2, false));
  39.         String pComboMatch = combineRE(p1,p2, true);
  40.         Matcher m = pCombo.matcher(haystack);
  41.         int s = 0;
  42.         while (m.find(s)){
  43.             s = m.start()+1;
  44.             String match = haystack.substring(m.start());
  45.             for (int i=match.length(); i>0; i--){
  46.                 String sMatch = match.substring(0,i);
  47.                 if (Pattern.matches(pComboMatch, sMatch)){
  48.                     toReturn.add(sMatch);
  49.                     if (!overlap){
  50.                         s = m.start()+i;
  51.                         break;
  52.                     }
  53.                 }
  54.             }
  55.         }
  56.         return toReturn.toArray(new String[]{});
  57.  
  58.     }
  59.     public static void main(String[] args){
  60.         String p1 = "a.*";
  61.         String p2 = ".*b";
  62.         String p = combineRE(p1, p2);
  63.         String s = "caabcbc";
  64.         System.out.println("p1: " + p1 + "\np2: " + p2 + "\np: " + p + "\ns: " + s);
  65.         Matcher m = Pattern.compile(p).matcher(s);
  66.         m = Pattern.compile("(?=4)").matcher("01234567890123456");
  67.         String[] noverlap = findAllCombinedRE(p1, p2, s, false);
  68.         for (int i=0; i<noverlap.length; i++){
  69.                 System.out.println(noverlap[i]);
  70.         }
  71.         System.out.println();
  72.         String[] overlap = findAllCombinedRE(p1, p2, s, true);
  73.         for (int i=0; i<overlap.length; i++){
  74.                 System.out.println(overlap[i]);
  75.         }
  76.     }
  77. }
Success #stdin #stdout 0.07s 380224KB
comments (?)
stdin
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Standard input is empty
stdout
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p1: a.*
p2: .*b
p: ^(?=a.*$)(?=.*b$).*
s: caabcbc
aabcb

aabcb
aab
abcb
ab
https://ideone.com/CBoBN5
language:
Java (HotSpot 12)
created:
12 years ago
visibility:
public

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