First Non Repeating Character

PROBLEM :

Given a string s consisting of lowercase Latin Letters, find the first non repeating character in s.

Input:

The first line contains T denoting the number of testcases. Then follows description of testcases.
Each case begins with a single integer N denoting the length of string. The next line contains the string s.

Output:


 For each testcase, print the first non repeating character present in string.

 Print -1 if there is no non repeating character.

Constraints:


 1<=T<=30
 1<=N<=100


Example:


Input :

3
5
hello
12
zxvczbtxyzvy
6
xxyyzz



Output :

h
c
-1
     
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SIMPLE c++ IMPLEMENTATION :
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#include<iostream>
using namespace std;
char Non_Repeating(char *,int) ;
int main()
 {
int t,no ;
char str[100],ele ;
cin>>t ;
while(t--)
{
   cin>>no ;
   cin>>str ;
 
   ele=Non_Repeating(str,no) ;
   if(ele=='1')
       cout<<-1 ;
   else
       cout<<ele ;
     
   cout<<endl ;
}
return 0;
}

char Non_Repeating(char *str,int l)
{
    int i ;
   
    int hash[256]={0} ;
   
    for(i=0;i<l;i++)
        hash[str[i]]++ ;
       
    for(i=0;i<l;i++)
    {
        if(hash[str[i]]==1)
            return str[i] ;
    }
    return '1' ;
}

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