Brute force Code for ARJN

#include<bits/stdc++.h>
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
using namespace std;
int main()
{
    fastio;
    int t;
    cin >> t;
    while(t--)
    {
        int a,b;
        cin >> a >> b;
        int i;
        int answer = 0;
        for(i = a; i <= b;i++)
        {
            int x = i;
            int digit_count[10] = {0};//initialize this array to zero
            while(x != 0)
            {
                int current_digit = x % 10;
                if(digit_count[current_digit] == 1)
                {
                    answer++;//one digit has repeated, so this number is part of the count.
                    break;
                }
                digit_count[current_digit]++;
                x = x / 10;//get the next digit
            }
        }
        cout << answer << '\n';
    }
    return 0;
}