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  1. import java.util.regex.*;
  2.  
  3. public class Main {
  4.     private static Pattern combineRe(Pattern p1, Pattern p2){
  5.         return Pattern.compile(combineRE(p1.pattern(), p2.pattern()));
  6.     }
  7.     private static String combineRE(String p1, String p2){
  8.         int groups1 = 0, groups2=0;
  9.         StringBuilder newP = new StringBuilder("(?=");
  10.         newP.append(p1);
  11.         newP.append("$)(?=");
  12.  
  13.         Pattern capturingGroup = Pattern.compile("(?<!\\\\)(\\\\\\\\)*\\((?!\\?)");
  14.         Matcher m = capturingGroup.matcher(p1);
  15.         while(m.find()) groups1 ++;
  16.  
  17.         m = capturingGroup.matcher(p2);
  18.  
  19.         while(m.find()) groups2 ++;
  20.         String new2 = p2;
  21.  
  22.         for(int i=1; i<=groups2; i++)
  23.             new2 = new2.replaceAll("(?<!\\\\)\\\\"+i, "\\\\" + (i+groups1));
  24.  
  25.         newP.append(new2);
  26.         newP.append(").*");
  27.         return newP.toString();
  28.     }
  29.     public static void main(String[] args){
  30.         String p1 = "a.*";
  31.         String p2 = ".*b";
  32.         String p = combineRE(p1, p2);
  33.         String s = "cacbc";
  34.         System.out.println("p1: " + p1 + "\np2: " + p2 + "\np: " + p + "\ns: " + s);
  35.         Matcher m = Pattern.compile(p).matcher(s);
  36.         int i = 0;
  37.         while (m.find()) {
  38.             System.out.println("find result " + (++i) + ": " + m.group());
  39.         }
  40.     }
  41. }
Success #stdin #stdout 0.06s 380224KB
comments (?)
stdin
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"a.*" ".*b" "cacbc"
stdout
copy 
p1: a.*
p2: .*b
p: (?=a.*$)(?=.*b).*
s: cacbc
find result 1: acbc
https://ideone.com/6oH3rA
language:
Java (HotSpot 12)
created:
11 years ago
visibility:
public

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