TOJ 1457. Beat the Spread!

很妙的一题，虽然很简单，但是有坑，一定要看

Superbowl Sunday is nearly here. In order to pass the time waiting for the half-time commercials and wardrobe malfunctions, the local hackers have organized a betting pool on the game. Members place their bets on the sum of the two final scores, or on the absolute difference between the two scores.

Given the winning numbers for each type of bet, can you deduce the final scores?

The first line of input contains n, the number of test cases. n lines follow, each representing a test case. Each test case givess and d, non-negative integers representing the sum and (absolute) difference between the two final scores. For each test case, output a line giving the two final scores, largest first. If there are no such scores, output a line containing "impossible". Recall that football scores are always non-negative integers.

Sample Input

240 2020 40

Output for Sample Input

30 10impossible

#include<iostream>using namespace std;int main(){int n,s,d,a,b;cin>>n;while(n--){cin>>s>>d;if(s<d)cout<<"impossible"<<endl;else{a=(s+d)/2;b=(s-d)/2;if(a+b!=s)cout<<"impossible"<<endl;elsecout<<a<<" "<<b<<endl;}}return 0;}