剑指offer(五十四)之字符流中第一个不重复的字符

import java.util.*;
public class Solution {
HashMap<Character, Integer> map=new HashMap();
ArrayList<Character> list=new ArrayList<Character>();
//Insert one char from stringstream
public void Insert(char ch)
{
if(map.containsKey(ch)){
map.put(ch,map.get(ch)+1);
}else{
map.put(ch,1);
}

list.add(ch);
}

//return the first appearence once char in current stringstream
public char FirstAppearingOnce()
{   char c='#';
for(char key : list){
if(map.get(key)==1){
c=key;
break;
}
}

return c;
}
}