import java.util.*;
class M{
  static String c(int a, int b, int c, int d){
    String r = "",
           w = "",
           l = "";
    List z = new ArrayList();
    int i,
        q = a+b-c-d;
    for(i = 0; i++ < c; w += 1);
    for(i = 0; i++ < d; l += 0);
    for( ; a-- - c > 0; z.add(1));
    for( ; b-- - d > 0; z.add(0));
    Collections.shuffle(z);
    for(i = 0; i < q; r += z.get(i++));
    return new StringBuilder(r).insert(new Random().nextInt(q), w+l)+"";
  }
 
  public static void main(String[] a){
    System.out.println(c(7, 3, 5, 2));
    System.out.println(c(171, 111, 10, 4));
  }
}

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