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#include<iostream>
#include<cstring>
#include<unordered_map>
#include<climits>
using namespace std;
 
 
char nonRepeatingCharacter(string str){
 
  //Write your code here
    int idx = 0;
    int arr[256] = {};
  	for(int i=0;i<str.length();i++){
    	arr[str[i]]++;  
  	}
    for(int i = 0; i<256 ; i++){
        if(arr[str[i]]==1){
            int idx = min(idx,i);
            return str[idx];
        }
    }
 
    return str[0];
}

/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/8/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status

Standard output is empty