題目連結：Sorting: Comparator | HackerRank
比較函式的撰寫
struct Player {
int score;
string name;
};
class Checker{
public:
static int comparator(Player a, Player b) {
if(a.score!=b.score) return a.score>b.score?0:-1;
return a.name<b.name?0:-1;
}
};