HDU1059 Dividing

这题  做了半天 ,明明 就是 套 模板的题,不知道 怎么老是WA...

顺便说一下这题 还有DFS解法;

#include<iostream>
 using namespace std;
 const int maxn = 10;
 int n[ maxn ];
 int sumv,V;
 int dp[ 60011 ];
 int max(int a,int b)
 {
     return a>b?a:b ;
 }
 void bag01( int cost,int weight ){
     for( int i=V;i>=cost;i-- ){
         dp[ i ]=max(dp[ i ],dp[ i-cost ]+weight);
     }
     return ;
 }
 void bagall( int cost ,int weight ){
    for( int i=cost;i<=V;i++ ){
        dp[ i ]=max( dp[ i ],dp[ i-cost ]+weight);
    }
     return ;
 }
 
void mul_bag( int cost,int weight,int num ){
     if( cost*num>=V ){
         bagall( cost,weight );
         return ;
    }
     int k=1;
     while( k<=num ){
         bag01( k*cost,k*weight );
         num-=k;
         k*=2;
    }
     bag01( num*cost,num*weight );
     return ;
 }
 int main()
 {
     int i,k=1;
     while(cin>>n[0]>>n[1]>>n[2]>>n[3]>>n[4]>>n[5],n[0]+n[1]+n[2]+n[3]+n[4]+n[5])
     {
         memset(dp,0,sizeof(dp));
        sumv=n[0]+n[1]*2+n[2]*3+n[3]*4+n[4]*5+n[5]*6;
         if(sumv%2==1)
         {
             printf("Collection #%d:
Can't be divided.

",k++);
             continue;
         }
         V=sumv/2;
        for(i=0;i<6;i++)
        {
             if(n[i]) mul_bag(i+1,i+1,n[i]);
        }
        if(V==dp[V]) printf("Collection #%d:
Can be divided.

",k++);
         else printf("Collection #%d:
Can't be divided.

",k++);
     }
     return 0;
 }

这题的DFS解法.

#include<iostream>  
#include<cstdio>  
using namespace std;  
int halfvalue;  
int a[7],sum,SUM,flag;  
  
void dfs(int v,int pre) 
{                        
    if(flag==1)    
        return;  
    if(v==halfvalue)  
    {  
        flag=1;  
        return;  
    }  
    for(int i=pre;i>=1;i--)  
    {  
       if(a[i]!=0)  
       {  
           if(v+i<=halfvalue)  
           {  
               a[i]--;//用过了就要减 
               dfs(v+i,i);  
               if(flag==1)  
                   break;  
           }  
       }  
    }  
    return;  
}  
int main()  
{  
    int c=1;  
    while(1)  
    {  
        sum=0,SUM=0;  
        for(int i=1;i<=6;i++)  
        {  
            scanf("%d",&a[i]);  
            sum+=a[i];  
            SUM+=i*a[i];  
        }  
        if(sum==0)  
            break;  
        if(SUM%2==1)  
        {  
            printf("Collection #%d:
Can't be divided.

",c++);  
            continue;  
        }  
        flag=0;  
        halfvalue=SUM/2;  
        dfs(0,6);  
        if(flag==1)  
            printf("Collection #%d:
Can be divided.

",c++);  
        else  
            printf("Collection #%d:
Can't be divided.

",c++);  
    }  
    system("pause");  
    return 0;  
}