【練習12】 貪心演算法 1001 FatMouse’ Trade

//模板開始#include <string>   #include <vector>   #include <algorithm>   #include <iostream>   #include <sstream>   #include <fstream>   #include <map>   #include <set>   #include <cstdio>   #include <cmath>   #include <cstdlib>   #include <ctime>#include<iomanip>#define SZ(x) (int(x.size()))using namespace std;int toInt(string s){istringstream sin(s); int t; sin>>t; return t;}template<class T> string toString(T x){ostringstream sout; sout<<x; return sout.str();}typedef long long int64;int64 toInt64(string s){istringstream sin(s); int64 t; sin>>t;return t;}template<class T> T gcd(T a, T b){ if(a<0) return gcd(-a, b);if(b<0) return gcd(a, -b);return (b == 0)? a : gcd(b, a % b);}//模板結束（通用部分）//hdoj專題 貪心演算法 1001 FatMouse' Trade#define ARRAY_SIZE 1005int main(){int m, n;int a[ARRAY_SIZE];int b[ARRAY_SIZE];double c[ARRAY_SIZE];int index;int count;double jb;ifstream ifs("shuju.txt", ios::in);while(cin>>m>>n && !(m == -1 && n == -1))//ifs>>m>>nifs{jb = 0;memset(a, 0, ARRAY_SIZE);memset(b, 0, ARRAY_SIZE);memset(c, 0, ARRAY_SIZE);for(int i = 0; i < n; i++){//ifs>>a[i]>>b[i];cin>>a[i]>>b[i];c[i] = (a[i] + 0.0) / b[i];}for(int j = 0; j < n; j++){index = 0;for(int i = 1; i < n; i++){if(c[i] > c[index]){index = i;}}if(m < b[index]){jb += m * c[index];c[index] = 0;break;}else{m -= b[index];jb += a[index];c[index] = 0;}}cout<<fixed<<setprecision(3)<<jb<<endl;}}