剑指offer五十四之字符流中第一个不重复的字符

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

public class Solution {
    LinkedHashMap<Character, Integer> lhm = new LinkedHashMap<Character, Integer>();
    //Insert one char from stringstream
    public void Insert(char ch)
    {
        //统计字符的个数，注意用LinkedHashMap
            if (lhm.containsKey(ch)) {
                lhm.put(ch, lhm.get(ch) + 1);
            } else {
                lhm.put(ch, 1);
            }
    }
    //return the first appearence once char in current stringstream
    public char FirstAppearingOnce()
    {
        //遍历map,寻找第一个只出现一次的数
        char num = 0;
        int flag=0; //判断有没有只出现一次的字符
        Set<Map.Entry<Character, Integer>> set = lhm.entrySet();
        for (Map.Entry<Character, Integer> es : set) {
            char key = es.getKey();
            int value = es.getValue();
            if (value == 1) {
                num = key;
                flag=1;//有只出现一次的字符
                break;
            }
        }
        //没有只出现一次的字符,返回‘#’
        if(flag==0){
            num=‘#‘;
        }
        flag=0;//复位，为下一次判断准备
        return num;
    }
}