GoogleQuestion

public class GoogleQuestion {
 public static void main(String args[]) {
 String a = "AMITABH BACHCHAN";
 String b = "RAJNIKANTH";

System.out.println("First String is :"+a);
 System.out.println("Second String is :"+b);

System.out.println(getCommonCharNSquard(a.toCharArray(), b.toCharArray()));
 System.out.println(getCommonCharN(a.toCharArray(), b.toCharArray()));
 }

public static char[] getCommonCharNSquard(char[] a, char[] b) {
 String ret ="";
 for(int i = 0; i < a.length; i++)
 for(int j=0; j <b.length; j++) {
 if(a[i] == b[j]) {
 if(ret.indexOf(a[i]) == -1) // if not previously , then add else dont add
 // ret is empty(nothing), so comparing it with a[i], which now contains intersection
 // of a,b and it with indexof(-1), as it is empty so automatically all values copies here.
 ret += a[i];

break; // it may reduce the processing time, but still n*n
 }
 }
 return ret.toCharArray();
 }

public static char[] getCommonCharN(char[] a, char[] b) {
 String ret = new String();
 boolean[] flags = new boolean[256]; //sizeOf(char)=256

for(int i = 0; i < b.length; i++)
 flags[b[i]] = true;

for(int j=0; j <a.length; j++)
 if(flags[a[j]] == true)
 {
 ret += a[j]; // order of a
 flags[a[j]] = false; // avoids repeation only..
 }
 return ret.toCharArray();
 }

}