HDU1864+dp+类似背包

和以前的背包方程有点不同。

注意：一张支票上可能有多个可能相同的项目

这是AC的代码。

/*
首先dp[i][j]:表示从前i个中选择j个，则转移方程为:
dp[i][j] = max( dp[ i-1 ][ j ](不选),dp[ i-1 ][ j-1 ]+val[i](选) );

一开始用dp[ i ][ j ]:表示从前i个中选某些个得到不超过j的最大值，发现过不了。。。只好看别人代码。。。
*/

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
using namespace std;
const int maxn = 55;
double val[ maxn ];
double dp[ maxn ][ maxn ];
const double eps = 1e-7;//必须加精度。。。
int main(){
    int n;
    double V;
    while( scanf("%lf%d",&V,&n)==2,n ){
        int tn;
        char str;
        double p;
        for( int i=0;i<n;i++ ){
            double sum = 0;
            int flag = 1;
            scanf("%d",&tn);
            double sum1,sum2,sum3;
            sum1 = sum2 = sum3 =0;
            while( tn-- ){
                scanf(" %c:%lf",&str,&p);
                if( str<'A'||str>'C' ) flag = -1;
                if( str=='A' ) sum1 += p;
                if( str=='B' ) sum2 += p;
                if( str=='C' ) sum3 += p;
                if( (sum1-600.0)>eps||(sum2-600.0)>eps||(sum3-600.0)>eps ) flag = -1;
                sum += p;
            }
            if( sum-1000.0>eps ) flag = -1;
            if( flag==-1 ) val[ i ] = 0;
            else val[ i ] = sum;
        }
        memset( dp,0,sizeof( dp ) );
        double res = 0;
        /*
        for( int i=0;i<n;i++ ){
            printf("val[%d]=%lf\n",i,val[i]);
            for( int j=n;j>=i;j-- ){
                dp[ j ] = max( dp[ j ],dp[ j-1 ]+val[i] );
                if( dp[j]>res&&dp[j]<V) res = dp[j];
            }
        }
        */
        for( int i=1;i<=n;i++ ){
        //printf("val[%d]=%lf\n",i-1,val[i-1]);
            for( int j=1;j<=i;j++ ){
                dp[ i ][ j ] = max( dp[ i-1 ][ j ],dp[ i-1 ][ j-1 ]+val[ i-1 ] );
                if( (dp[i][j]-V<eps)&&(dp[i][j]-res>eps) ) res = dp[i][j];
                //printf("dp[%d][%d]=%lf\n",i,j,dp[i][j]);
            }
        }
        printf("%.2lf\n",res);
    }
    return 0;
}
        
        

这是用100*money的AC代码。

/*
dp类似背包
*/
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
#include<iostream>
#include<queue>
#include<map>
#include<math.h>
using namespace std;
typedef long long ll;
//typedef __int64 int64;
const int inf = 0x7fffffff;
const double pi=acos(-1.0);
const double eps = 1e-6;

struct node{
    int vis;
    int m;
    int sum;
}a[ 36 ];
int dp[ 5000006 ];

int main(){
    int V,n;
    double tt;
    char name;
    while( scanf("%lf%d",&tt,&n)==2 ){
        if( n==0 ) break;
        V = tt*100;
        for( int i=0;i<n;i++ ){
             scanf("%d",&a[i].m);
             a[i].vis = true;
             int sum = 0;
             int sum1,sum2,sum3;
             sum1 = sum2 = sum3 = 0;
             for( int j=0;j<a[i].m;j++ ){
                 scanf(" %c:%lf",&name,&tt);
                 sum = (int)(tt*100.0);
                 if( name<'A'||name>'C' ) a[i].vis = false;
                 if( name=='A' ) sum1 += sum;
                 if( name=='B' ) sum2 += sum;
                 if( name=='C' ) sum3 += sum;
                 if( sum1>60000||sum2>60000||sum3>60000 ) a[i].vis = false;
             }
             if( sum>100000 ) a[i].vis = false;
             if( a[i].vis==true ) a[i].sum = sum1+sum2+sum3;
             else a[i].sum = 0;
         }
         memset( dp,0,sizeof( dp ) );
         int res = 0;
         for( int i=0;i<n;i++ ){
             for( int k=V;k>=a[i].sum;k-- ){
                 dp[ k ] = max( dp[k],dp[k-a[i].sum]+a[i].sum );
                 res = max( res,dp[k] );
             }
         }
         printf("%.2lf\n",(double)res/100.0);
    }
    return 0;
}

这是一开始wa的代码。。。

/*
dp类似背包
*/
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
#include<iostream>
#include<queue>
#include<map>
#include<math.h>
using namespace std;
typedef long long ll;
//typedef __int64 int64;
const int maxn = 105;
const int inf = 0x7fffffff;
const double pi=acos(-1.0);
const double eps = 1e-8;

struct node{
    int vis;
    int m;
    int sum;
    //int p[ 2005 ];
}a[ 36 ];
int dp[ 5000005 ];

int main(){
    int V,n;
    double tt;
    char name;
    while( scanf("%lf%d",&tt,&n)==2 ){
        if( n==0 ) break;
         V = tt*100;
         for( int i=0;i<n;i++ ){
             scanf("%d",&a[i].m);
             a[i].vis = true;
             double sum = 0;
             for( int j=0;j<a[i].m;j++ ){
                 scanf(" %c:%lf",&name,&tt);
                 sum += tt;
                 //a[i].p[j] = tt*100;
                 if( tt>600.0||name<'A'||name>'C'||sum>1000.0 ) a[i].vis = false;
                 //if( name<'A'||name>'C' ) a[i].p[j] = 0;
             }
             if( a[i].vis==true ) a[i].sum = sum*100;
             else a[i].sum = 0;
         }
         memset( dp,0,sizeof( dp ) );
         int res = 0;
         for( int i=0;i<n;i++ ){
             //if( a[i].vis==true ){
                 //for( int j=0;j<a[i].m;j++ ){
                     for( int k=V;k>=a[i].sum;k-- ){
                         dp[ k ] = max( dp[k],dp[k-a[i].sum]+a[i].sum );
                         res = max( res,dp[k] );
                     }
                 //}
             }
             //else dp[ k ] = max( dp[k],dp[k-a[i].sum]+a[i].sum );
         //}
         printf("%.2lf\n",res/100.0);
    }
    return 0;
}