hdoj1864

平时都是搜索回溯慢，背包快，这道题倒是个特例，背包500ms，搜索0ms。

Problem : 1864 ( 最大报销额 )     Judge Status : Accepted
RunId : 2682097    Language : G++    Author : huwenbiao
Code Render Status : Rendered By HDOJ G++ Code Render Version 0.01 Beta

/***************************************************************\
 *Author:Hu Wenbiao
 *Created Time: Sun 25 Jul 2010 03:22:16 PM CST
 *File Name: main.cpp
 *Description:01背包
\***************************************************************/
//*========================*Head File*========================*\\

#include<iostream>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
/*----------------------*Global Variable*----------------------*/
double Q,price,a,b,c;
int f[3000010],N,m,cost,V;
char type;
bool flag;
//*=======================*Main Program*=======================*//
using namespace std;

int main(){
    //freopen("input","r",stdin);
    while(scanf("%lf%d",&Q,&N)!=EOF&&N){
        V=Q*100;
        memset(f,0,(1+V)*sizeof(int));
        while(N--){
            scanf("%d",&m);
            a=b=c=0;
            flag=true;
            if(m==0)continue;
            while(m--){
                scanf(" %c:%lf",&type,&price);
                if(type=='A')
                  a+=price;
                else if(type=='B')
                  b+=price;
                else if(type=='C')
                  c+=price;
                else
                  flag=false;
            }
            if(a>600||b>600||c>600||a+b+c>1000)
              flag=false;
            if(!flag)continue;
            cost=(a+b+c)*100;
            for(int v=V;v>=cost;v--)
              f[v]=max(f[v],f[v-cost]+cost);
        }
        double ans=f[V];
        printf("%.2lf\n",ans/100);
    }
}