[topcoder]LongLongTripDiv2

http://community.topcoder.com/stat?c=problem_statement&pm=13091

解方程，对中国孩子太简单了。

#include <vector>

#include <iostream>

using namespace std;



class LongLongTripDiv2 {

public:

    string isAble(long long D, int T, int B) {

        long long diff = (D - T);

        if (diff % (B - 1) != 0)

            return "Impossible";

        long long b = diff / (B - 1);

        long long a = T - b;

        if (b >= 0 && a >= 0)

            return "Possible";

        return "Impossible";

    }

};