/**
 * 陣列交集，並集，差集
 * @author Administrator
 *
 */
public class cal3 {

    public static void main(String[] args) {
        String[] arr1 = {"abc", "df", "abc"};   
        String[] arr2 = {"abc", "cc", "df", "d", "abc"};   
        intersect(arr1, arr2);
    }

    //並集
    public static Set union(String
 
[] arr1, String[] arr2) {
        Set<String> set = new HashSet<String>();
        for (String str : arr1) {   
            set.add(str);   
        }   
        for (String str : arr2) {   
            set.add(str);   
        }  
        return set;
    }
    //差集(在陣列A中不在陣列B中)
    public static List<String
 
> minus(String[] arr1, String[] arr2) {   
        LinkedList<String> list = new LinkedList<String>();   
        LinkedList<String> history = new LinkedList<String>();   
        String[] longerArr = arr1;   
        String[] shorterArr = arr2;   
        //找出較長的陣列來減較短的陣列   
 

        if (arr1.length > arr2.length) {   
            longerArr = arr2;   
            shorterArr = arr1;   
        }   
        for (String str : longerArr) {   
            if (!list.contains(str)) {   
                list.add(str);   
            }   
        }   
        for (String str : shorterArr) {   
            if (list.contains(str)) {   
                history.add(str);   
                list.remove(str);   
            } else {   
                if (!history.contains(str)) {   
                    list.add(str);   
                }   
            }   
        }  
        return list;
    }   

    //交集
    public static List<String> intersect(String[] arr1, String[] arr2) { 

        Map<String, Boolean> map = new HashMap<String, Boolean>();   
        LinkedList<String> list = new LinkedList<String>();   
        for (String str : arr1) {   
            if (!map.containsKey(str)) {   
                map.put(str, Boolean.FALSE);   
            }   
        }   
        for (String str : arr2) {   
            if (map.containsKey(str)) {   
                map.put(str, Boolean.TRUE);   
            }   
        }   

        for (Entry<String, Boolean> e : map.entrySet()) {   
            if (e.getValue().equals(Boolean.TRUE)) {   
                list.add(e.getKey());   
                System.out.println(e.getKey());
            }   
        }   
        return list;
    }   
}