HDU 2111 Saving HDU

明显的贪心

  
    

   
     #include 
   
     <
   
     stdio.h
   
     >
   
     
#include 
   
     <
   
     iostream
   
     >
   
     
#include 
   
     <
   
     vector
   
     >
   
     
#include 
   
     <
   
     algorithm
   
     >
   
     

   
     using
   
      
   
     namespace
   
      std;

   
     struct
   
      BaoBei{
 
   
     int
   
      p, m;
 
   
     double
   
      val;
};


   
     bool
   
      cmp(
   
     const
   
      BaoBei 
   
     &
   
     a, 
   
     const
   
      BaoBei 
   
     &
   
     b){ 
   
     

   
      
   
     return
   
      a.p 
   
     >
   
      b.p;　　　　// >号 降序排序
}

   
     int
   
      main(){
 
   
     int
   
      v, n;
 vector
   
     <
   
     BaoBei
   
     >
   
      vec;
 
   
     while
   
     ( cin 
   
     >>
   
      v, v ){
 cin >> n;
   
     
 vec.clear();
 BaoBei tmp;
 
   
     for
   
     (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      n; 
   
     ++
   
     i){
 cin 
   
     >>
   
      tmp.p 
   
     >>
   
      tmp.m;
 vec.push_back(tmp);
 }
 sort(vec.begin(), vec.end(), cmp);
 
   
     int
   
      ans 
   
     =
   
      
   
     0
   
     ;
 
   
     for
   
     (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      n; 
   
     ++
   
     i){
 
   
     if
   
     (v 
   
     <=
   
      
   
     0
   
     ){
 
   
     break
   
     ;
 } 
   
     else
   
      {
 
   
     if
   
     ( vec[i].m 
   
     <=
   
      v ){
 ans 
   
     +=
   
      vec[i].p 
   
     *
   
      vec[i].m;
 v 
   
     -=
   
      vec[i].m;
 } 
   
     else
   
      {
 ans 
   
     +=
   
      v 
   
     *
   
      vec[i].p;
 v 
   
     -=
   
      v;
 }
 }
 }
 cout 
   
     <<
   
      ans 
   
     <<
   
      endl;
 }
 
   
     return
   
      
   
     0
   
     ;
}