C++ 代码问题分析与优化：石头问题代码解析及改进

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

struct stone { long long size_, power; long double goods;

long double sp()
{
    goods = 1.0000000000000000000000000000000 * size_ / power;
    return goods;
}

};

bool cmp(stone x, stone y) { if(std::abs(x.goods - y.goods) > 1e-9) { return x.goods > y.goods; } return x.power < y.power; }

int main() { long long a, b, c; cin >> a >> b >> c;

vector<stone> jw(b);
for(int i = 0; i < b; i++)
{
    cin >> jw[i].size_ >> jw[i].power;
}

for(int i = 0; i < b; i++)
{
    jw[i].sp();
}

sort(jw.begin(), jw.end(), cmp);

for(int i = 0; i < b; i++)
{
    c -= jw[i].power;
    a -= jw[i].size_;

    if(c < 0)
    {
        cout << 'Impossible';
        return 0;
    }
    else if(a <= 0)
    {
        cout << c;
        return 0;
    }
}

cout << 'Impossible';
return 0;

}