hdoj1009_FatMouse' Trade（贪心）

#include<iostream>#include<vector>#include<algorithm>#include<utility>#include<iomanip>using namespace std;vector<pair<int,int>> v;bool cmp(pair<int, int> p1, pair<int, int> p2){    return (p1.first*1.0 / p1.second) > (p2.first*1.0 / p2.second);}double solve(int m, int n){    sort(v.begin(), v.end(), cmp);    int i = 0;    double ans = 0;    while (i<n&&m > v[i].second)    {        m -= v[i].second;        ans += v[i].first;        i++;    }    if (i < n&&m>0)    {        ans += m *1.0/ v[i].second*v[i].first;    }    return ans;}int main(){    int m, n;    while (cin >> m >> n&&m != -1)    {        v.clear();        for (int i = 0; i < n; i++)        {            int j, f;            cin >> j>>f;            v.push_back(make_pair(j, f));        }        cout << setiosflags(ios::fixed) << setprecision(3) << solve(m, n) << endl;    }    return 0;}