题解 | #找出字符串中第一个只出现一次的字符#

import java.util.*;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNextLine()){
            String str = sc.nextLine();
            char[] ch = str.toCharArray();
            Map<Character,Integer> chMap = new LinkedHashMap();
            for (int i = 0; i < ch.length; i++) {
                if(chMap.containsKey(ch[i])){
                    chMap.put(ch[i],chMap.get(ch[i])+1);
                }
                else{
                    chMap.put(ch[i],1);
                }
            }
            Character chRes = null;
            for (Character c:  chMap.keySet()) {
                 if(chMap.get(c) == 1){
                     chRes=c;
                     break;
                 }
            }
            if(chRes==null){
                System.out.println("-1");
            }
            else {
                System.out.println(chRes);
            }
        }
    }

}