[Poj3311] HIE with the pie

[Poj3311] HIE with the pie

Question: 
A person who delivers takeaways should depart from and go through all the locations before returning to the store (that is,), at the minimum cost.
Input 
1 <= n <= 10
Output 
An integer represents the minimum cost.
Sample Input 
3
0 1 10 10
1 0 1 2
10 1 0 10
10 2 10 0
0
Sample output 
8

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Dynamic State compression Planning

F [s] [I]: indicates the point that has passed the S state, most of which stays at the I point. Of course, the I point must be in the S state, the shortest path.

F [s] [I] = min (F [s '] [J] + dis [J] [I]), the condition s is only less I point than the S state

Of course, the distance between I and 0 must be added.

Don't forget Floyd !!

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 1 #include<cstdio> 2 #include<iostream> 3 #include<algorithm> 4 #include<cstring> 5 using namespace std; 6 int f[1<<10][11]; 7 int dis[11][11],n; 8  9 void init()10 {11     memset(f,0x7f,sizeof(f));12     for(int i=0;i<n;++i)f[(1<<i)][i+1]=dis[0][i+1];13 }14 void dp(int s,int las)15 {16     if(s==0)return ;17     if(f[s][las]!=0x7f7f7f7f)return ;18     int ss=s^(1<<(las-1));19     for(int i=0;i<n;++i)20     {21         if((ss&(1<<i)))22         {23             dp(ss,i+1);24             f[s][las]=min(f[s][las],f[ss][i+1]+dis[i+1][las]);25         }26     }27 }28 void floyd()29 {30     for(int k=0;k<=n;++k)31         for(int i=0;i<=n;++i)32             for(int j=0;j<=n;++j)33                 if(dis[i][j]>dis[i][k]+dis[k][j])dis[i][j]=dis[i][k]+dis[k][j];34 }35 int main()36 {37     while(scanf("%d",&n)==1 && n)38     {39         for(int i=0;i<=n;++i)40             for(int j=0;j<=n;++j)41                 scanf("%d",&dis[i][j]);42         floyd();43         init();44         long long ans=0x7fffffffffffffff;45         for(int i=1;i<=n;++i)46         {47             dp((1<<n)-1,i);48             if(f[(1<<n)-1][i]+dis[i][0]<ans)ans=f[(1<<n)-1][i]+dis[i][0];49         }50         printf("%lld\n",ans);51     }52     return 0;53 }

View code

 

[Poj3311] HIE with the pie