HDU 3001 (Pressure dp+ three-in)

Regardless of the binary, it is a logical concept, (last six is used to convert multidimensional data) The core idea is the TSP. The preprocessing here is quite ingenious, calculating the modulus vis[][on each bit in each State].

TSP:DP[I][J] In the I state, the optimal solution with J ending. Two kinds of transfer are: I for everyone, everyone for me.

#include <cstdio> #include <iostream> #include <cstring> #include <algorithm> #define MAXN 60000 #define INF 0x3f3f3f3fconst double eps=1e-8;using namespace Std;int dp[maxn][12];int maps[13][12];int vis[maxn][12];int    State[12];int n,m;void init () {state[0]=1;    for (int i=1;i<11;i++) state[i]=state[i-1]*3;        for (int i=0;i<=state[10];i++) {int x=i;    for (int j=0;j<10;j++) vis[i][j]=x%3,x/=3;    }}int Main () {//Freopen ("In.txt", "R", stdin);        while (~SCANF ("%d%d", &n,&m)) {init ();        memset (maps,0x3f,sizeof (maps));            for (int i=0;i<m;i++) {int u,v,k;            scanf ("%d%d%d", &u,&v,&k);        Maps[u-1][v-1]=maps[v-1][u-1]=min (MAPS[U-1][V-1],K);        } int tag,ans=inf;        Memset (Dp,0x3f,sizeof (DP));        for (int i=0;i<n;i++) dp[state[i]][i]=0;            for (int i=0;i<state[n];i++) {tag=1;  for (int j=0;j<n;j++)          {if (vis[i][j]==0) tag=0;//This judgment is particularly ingenious, because J will loop, inside the case where I is stored if (dp[i][j]==inf) continue; for (int k=0;k<n;k++) {if (k!=j && vis[i][k]<2 && ma Ps[k][j]!=inf) Dp[i+state[k]][k]=min (dp[i+state[k]][k],dp[i][j]+maps[j][k]);//The last written one is the back, this is the rear Forward, better to write.        Everyone for me, I am for everyone} if (tag) for (int j=0;j<n;j++) ans=min (Ans,dp[i][j]);        } if (ans = = inf) ans =-1;    cout<<ans<<endl; } return 0;}

HDU 3001 (Pressure dp+ three-in)