查找字符串中所有不重复的字符

Question

can you help me to to this java program? i have a two string i need to determine what are the characters that has no repeated letters. the inputs are: love, life the out put will be: ovif

it will removed all the character that has a duplicate.

here's the code that i have but it only print and find the letters that has duplicate.

public static void main(String[] args) {
    Map<Character, Integer> map = new HashMap<Character, Integer>(); 

    input = new Scanner(System.in);
    String aw, bw;

    System.out.println("Input First Word: ");
    aw=input.next();
    System.out.println("Input Second Word: ");
    bw=input.next();
    String s = aw+bw;
    char[] chars = s.toCharArray();

    for(Character ch:chars){
      if(map.containsKey(ch)){
         map.put(ch, map.get(ch)+1);
      } else {
         map.put(ch, 1);
      }
    }

    Set<Character> keys = map.keySet();


    for(Character ch:keys){
      if(map.get(ch) > 1){
        System.out.println(ch+" ");
      }
    }
}

i want to print the characters that it removed in that program.

Answer 1

for(Character ch:keys){
  if(map.get(ch) == 1){
    System.out.println(ch+" ");
  }
}

Will print out all the characters that appear once. You add every character in both strings to the map, so characters which only appear once will have value 1.

Answer 2

A Set is excellent for checking history.

public void test() {
    String s = "love life";
    Set<Character> unique = new HashSet<>();
    Set<Character> duplicate = new HashSet<>();
    for (char c : s.toCharArray()) {
        // Have we seen this one before already.
        if (!duplicate.contains(c)) {
            if (!unique.add(c)) {
                // It was already there.
                unique.remove(c);
                // Mark it as duplicate.
                duplicate.add(c);
            }

        }
    }
    System.out.println("Unique:" + Arrays.toString(unique.toArray(new Character[0])));
}

Manipulating Set s is simple:

Set<Character> inString(String s) {
    Set<Character> in = new HashSet<>();
    for (char c : s.toCharArray()) {
        in.add(c);
    }
    return in;
}

public void test() {
    Set<Character> inFirst = inString("glass");
    Set<Character> inSecond = inString("bass");
    Set<Character> inFirstButNotInSecond = new HashSet<>(inFirst);
    inFirstButNotInSecond.removeAll(inSecond);
    System.out.println("In first but not in second:" + inFirstButNotInSecond);
}