华为机试-找出字符串中第一个只出现一次的字符

import java.util.Scanner;

public class FirstSingleChar {

public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sc=new Scanner(System.in);
while(sc.hasNext())
{
String s=sc.next();
firstSinglechar(s);
}
sc.close();
}
public static void firstSinglechar(String s)
{
char chs[]=s.toCharArray();
int a[]=new int[chs.length];
for(int i=0;i<chs.length;i++)
{
for(int j=i+1;j<chs.length;j++)
{
if(chs[i]==chs[j])
{
a[i]=a[j]=-1;
}
}
}
for(int i=0;i<chs.length;i++)
{
if(a[i]==0)
{
System.out.println(chs[i]);
return;
}
}
System.out.println(-1);
}
}