Addrev.java

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Addrev {

    public static void main(String[] args)throws Exception {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

        int count = Integer.parseInt(in.readLine());
        Integer input[][] = new Integer[count][2];

        for(int i = 0; i < count; i++) {
            StringTokenizer tk = new StringTokenizer(in.readLine());
            input[i][0] = Integer.parseInt(tk.nextToken());
            input[i][1] = Integer.parseInt(tk.nextToken());
        }

        for(int i = 0; i < count; i++) {
            int sum = reverse(input[i][0]) + reverse(input[i][1]);
            System.out.println(reverse(sum));
        }

    }

    static int reverse(int num) {

        int rev = 0;

        while(num != 0) {
            int digit = num % 10;
            rev = rev * 10 + digit;

            num /= 10;
        }

        return rev;
    }
}

https://www.spoj.com/problems/ADDREV/