HDU 3001 travelling (shaped pressure dp,3)

Test instructions

The n<=10 point is given, and there is an no-direction graph with M-edge. Q: Can you start at any point and go through the same point 2 times and traverse the minimum cost of all points?

Ideas:

The main thing is to card your memory, because at most can go through the same point 2 times, so can only be used 3 binary to represent, 3 binary can first hit the table out. In the walk when the attention can only walk 2 times, the other and ordinary TSP pressure dp is the same. Note: Heavy side, self-ring and so on, old terrier.

1 //#include <bits/stdc++.h>2#include <iostream>3#include <cstdio>4#include <cstring>5#include <cmath>6#include <map>7#include <algorithm>8#include <vector>9#include <iostream>Ten #definePII pair<int,int> One #defineINF 0x3f3f3f3f A #defineLL Long Long - #defineULL unsigned long Long - using namespacestd; the Const DoublePI = ACOs (-1.0); - Const intn= One; - intG[n][n], dp[60000][n], up[n], bit[n]; -  + intDecodeintS//decoding the state s - { +     intCnt=0; A      for(intI=1; S i++) at     { -bit[i]=s%3; -S/=3; -         if(Bit[i]) cnt++; -     } -     returnCNT; in } -  to intCalintN) + { -Memset (DP,0x3f,sizeof(DP)); the     intans=INF; *      for(intI=1; i<=n; i++) dp[up[i-1]][i]=0;//set each starting point to 0 without affecting the result $      for(ints=1; s<=up[n]; s++)Panax Notoginseng     { -         intCnt=decode (s);//CNT indicates the number of points that have been traversed the          for(intI=1; i<=n; i++)//Enumerate intermediate points +         { A             if(bit[i]>0)//Make sure you've traversed the I point the             { +                  for(intj=1; j<=n; J + +)//Enumerate Endpoints -                 { $                     if(bit[j]==2)Continue;//I 've been through it 2 times. $                     BOOLFlag=cnt==n?true:false;//in order to update the answer -                     if(bit[j]==0&&cnt+1==n) flag=true; -                     int&q=dp[s+up[j-1]][j]; the                     if(Q>dp[s][i]+g[i][j]) q=dp[s][i]+G[i][j]; -                     if(flag) ans=min (ans, q);Wuyi                 } the             } -         } Wu     } -     returnans; About } $  - voidInit ()//3 binary first hit the table - { -     intA=3; Aup[0]=1; +      for(intI=1; i<n; i++) the     { -up[i]=A; $a*=3; the     } the } the  the  - intMain () in { the     //freopen ("Input.txt", "R", stdin); the init (); About     intN, M, A, B, C; the      while(~SCANF ("%d%d", &n,&m))//up to 2 times per point the     { theMemset (G,0x3f,sizeof(g)); +          for(intI=1; i<=n; i++) g[i][i]=0; -          for(intI=0; i<m; i++) the         {Bayiscanf"%d%d%d",&a,&b,&c); theg[a][b]=g[b][a]=min (g[a][b],c); the         } -         if(n==1) -         { thePuts"0"); the             Continue; the         } the         intans=cal (n); -printf"%d\n", ans==inf?-1: ans); the     } the     return 0; the}

AC Code

HDU 3001 travelling (shaped pressure dp,3)