题解 | #找出字符串中第一个只出现一次的字符#

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            String str = sc.next();
            Map<Character, Integer> map = new LinkedHashMap<>();
            for (int i = 0; i < str.length(); i++) {
                if(map.containsKey(str.charAt(i))){
                    map.put(str.charAt(i),map.get(str.charAt(i)) + 1);
                }else{
                    map.put(str.charAt(i), 1);
                }
            }
            char ch = 0;
            for(Map.Entry<Character,Integer> entry : map.entrySet()){
                if(entry.getValue() == 1){
                    ch = entry.getKey();
                    break;
                }
            }
            if(ch == 0){
                System.out.println(-1);
            }else{
                System.out.println(ch);
            }
        }
    }
}