笔试算法《找出字符串中第一个只出现一次的字符》

描述
找出字符串中第一个只出现一次的字符

输入描述：
输入几个非空字符串

输出描述：
输出第一个只出现一次的字符，如果不存在输出-1

示例1
输入：
asdfasdfo
aabb

输出：
o
-1

代码

public class Huawei找出字符串中第一个只出现一次的字符 {

    public static void main(String[] args) throws IOException {
        my();
        niuke();
    }


    public static void my() throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String a = null;
        StringBuilder builder=new StringBuilder();
        while ((a = br.readLine()) != null) {
            LinkedHashMap<Character, Integer> map = new LinkedHashMap<>();
            char[] chars = a.toCharArray();
            for (int i = 0; i < chars.length; i++) {
                if (map.containsKey(chars[i])) {
                    map.put(chars[i], -1);
                } else {
                    map.put(chars[i], 1);
                }
            }

            String result = "-1";
            for (Map.Entry<Character, Integer> entry : map.entrySet()) {
                Character k = entry.getKey();
                Integer v = entry.getValue();
                if (v == 1) {
                    result = String.valueOf(k);
                    break;
                }
            }
            builder.append(result).append("\n");
        }
        System.out.println(builder.toString());

    }

    /**
     * 牛客网解法
     */
    public static void niuke() throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = null;
        int term = 0;
        char[] c = null;
        while ((str = br.readLine()) != null) {
            term = 0;
            c = str.toCharArray();
            for (int i = 0; i < c.length; i++) {
                term = 0;
                for (int j = 0; j < c.length; j++) {
                    if (c[i] == c[j]) {
                        term++;
                    }
                }
                if (term == 1) {
                    System.out.println(c[i]);
                    break;
                }
            }
            if (term != 1) {
                System.out.println(-1);
            }
        }
        br.close();
    }
}