Problem A: Bits and Pieces

Let A and B be non-negative integers and let C = A&B and D = A|B. Given C and D, can you find A and B such that the absolute difference (|A-B|) is minimal?

(A&B and A|B are bitwise AND and OR respectively, represented with symbols & and | in the programming languages used in this contest)

Input Format

The input starts with an integer T - the number of test cases (T <= 100). T cases follow on each subsequent line, each of them containing integers C and D (0 <= C,D < 2^31).

Output Format

For each test case, print integers A and B on a line such that A&B=C, A|B=D, A<=B and B-A is minimal. If there are no such A and B, print -1 on the line instead.

Sample Input

3
2 3
3 2
3 15

Sample Output

2 3
-1
7 11

#include <stdio.h>
void solve(int c, int d) {
    int i, a, b;
    for(i = 30; i >= 0; i--) {
        if((c&(1<<i)) != 0 && (d&(1<<i)) == 0) {
            puts("-1");
            return;
        }
    }
    a = c, b = c;
    int flag = 0;
    for(i = 30; i >= 0; i--) {
        if((c&(1<<i)) == 0) {
            if((d&(1<<i)) != 0) {
                if(flag)
                    a |= 1<<i;
                else
                    b |= 1<<i;
                flag = 1;
            }
        }
    }
    printf("%d %d\n", a, b);
}
int main() {
    int t, c, d;
    scanf("%d", &t);
    while(t--) {
        scanf("%d %d", &c, &d);
        solve(c, d);
    }
    return 0;
}