1247A - Forgetting Things - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;

int main()
{
    int a,b;
    cin >> a >> b;
    if(a == b) cout << a*10 << " " << a*10+1 << endl; //情况1
    else if(a + 1 == b) cout << b*10-1 << " " << b*10 << endl; //情况2，此时b*10-1与a*10+9等同
    else if(a == 9 && b == 1) cout << "9 10" << endl; //情况3
    else cout << -1 << endl; //无解
    return 0;
}