Sorting Strings and extracting common elements of two String arrays in Java

Question

I was asked to write down a Java function sharedStr that by given 2 sorted arrays of Strings, returns the number of Strings that appea

Answer 1

Because the arrays are sorted, you can step through them knowing you're walking them in order.

import java.util.List;
import java.util.LinkedList;
class StringTest {
    static List sharedStrings(String[] a, String[] b) {
        List result = new LinkedList();
        int apos = 0;
        int bpos = 0;
        while(!(apos == a.length || bpos == b.length)) {
            int comp = a[apos].compareTo(b[bpos]);
            if(comp == 0) result.add(a[apos++]);
            else if(comp > 0) bpos++;
            else apos++;
        }
        return result;
    }
    public static void main(String[] args) {
        String[] a = new String[]{"this","is","a","test"};
        String[] b = new String[]{"test","for","a","party"};

        java.util.Arrays.sort(a);
        java.util.Arrays.sort(b);

        List result = sharedStrings(a,b);
        for(String s : result) System.out.println(s);

    }
}