【剑指offer-Java版】35第一个只出现一次的字符

public class _Q35<T> {

public char FirstNotRepeatingChar(char chars[]){
if(chars == null) return '\0'; // 不知java中返回个什么好

int hash[] = new int[256];
for(int i=0; i<chars.length; i++){
hash[chars[i]]++;
}

int resultIndex = 0;
for(int i=0; i<chars.length; i++){
if(hash[chars[i]] == 1){
resultIndex = i;
break;
}
}

if (resultIndex != 0) {
return chars[resultIndex];
} else {
return '\0';
}
}

}

public class _Q35Test extends TestCase {

_Q35 firstNoRepeat = new _Q35();

public void test(){

String str1 = "abaccdeff";
String str2 = "aaaacba";
String str3 = "";
String str4 = "abcabc";

System.out.println(firstNoRepeat.FirstNotRepeatingChar(str1.toCharArray()));
System.out.println(firstNoRepeat.FirstNotRepeatingChar(str2.toCharArray()));
System.out.println(firstNoRepeat.FirstNotRepeatingChar(str3.toCharArray()));
System.out.println(firstNoRepeat.FirstNotRepeatingChar(str4.toCharArray()));

}
}