[状压dp]HDOJ3001 Travelling

  1 #include <cstdio>
  2 #include <cstdlib>
  3 #include <cstring>
  4 #include <climits>
  5 #include <cctype>
  6 #include <cmath>
  7 #include <string>
  8 #include <sstream>
  9 #include <iostream>
 10 #include <algorithm>
 11 #include <iomanip>
 12 using namespace std;
 13 #include <queue>
 14 #include <stack>
 15 #include <vector>
 16 #include <deque>
 17 #include <set>
 18 #include <map>
 19 typedef long long LL;
 20 typedef long double LD;
 21 #define pi acos(-1.0)
 22 #define lson l, m, rt<<1
 23 #define rson m+1, r, rt<<1|1
 24 typedef pair<int, int> PI;
 25 typedef pair<int, PI> PP;
 26 #ifdef _WIN32
 27 #define LLD "%I64d"
 28 #else
 29 #define LLD "%lld"
 30 #endif
 31 //#pragma comment(linker, "/STACK:1024000000,1024000000")
 32 //LL quick(LL a, LL b){LL ans=1;while(b){if(b & 1)ans*=a;a=a*a;b>>=1;}return ans;}
 33 //inline int read(){char ch=‘ ‘;int ans=0;while(ch<‘0‘ || ch>‘9‘)ch=getchar();while(ch<=‘9‘ && ch>=‘0‘){ans=ans*10+ch-‘0‘;ch=getchar();}return ans;}
 34 //inline void print(LL x){printf(LLD, x);puts("");}
 35 //inline void read(int &x){char c = getchar();while(c < ‘0‘) c = getchar();x = c - ‘0‘; c = getchar();while(c >= ‘0‘){x = x * 10 + (c - ‘0‘); c = getchar();}}
 36 
 37 #define INF 2139062143
 38 int dp[60005][12];
 39 int mp[12][12];
 40 int num[12], vis[60005][12];
 41 void init()
 42 {
 43     num[0]=1;
 44     for(int i=1; i<=10; i++)
 45         num[i]=num[i-1]*3;
 46     memset(vis, -1, sizeof(vis));
 47     for(int i=0; i<=num[10]; i++)
 48     {
 49         int x=i;
 50         for(int j=0; j<=10; j++)
 51         {
 52             vis[i][j]=x%3;
 53             x/=3;
 54         }
 55     }
 56 }
 57 int main()
 58 {
 59 #ifndef ONLINE_JUDGE
 60     freopen("in.txt", "r", stdin);
 61     freopen("out.txt", "w", stdout);
 62 #endif
 63     init();
 64     int n, m;
 65     while(~scanf("%d%d", &n, &m))
 66     {
 67         memset(dp, 127, sizeof(dp));
 68         memset(mp, 127, sizeof(mp));
 69         for(int i=0; i<n; i++)
 70             dp[num[i]][i]=0;
 71         while(m--)
 72         {
 73             int a, b, c;
 74             scanf("%d%d%d", &a, &b, &c);
 75             mp[a-1][b-1]=mp[b-1][a-1]=min(mp[a-1][b-1], c);
 76         }
 77         int ans=INF;
 78         for(int i=0;i<num[n];i++) // n个城市走过次数的状态i
 79         {
 80             bool flag=0;
 81             for(int j=0;j<n;j++)   // 当前在j
 82             {
 83                 if(!vis[i][j])
 84                     flag=1;
 85                 if(dp[i][j]==INF)
 86                     continue;
 87                 for(int k=0;k<n;k++)   // 走去 k
 88                     if(j!=k)
 89                     {
 90                         if(vis[i][k]>=2)
 91                             continue;
 92                         if(mp[j][k]==INF)
 93                             continue;
 94                         dp[i+num[k]][k]=min(dp[i+num[k]][k], dp[i][j]+mp[j][k]);
 95                     }
 96             }
 97             if(!flag)
 98                 for(int j=0;j<n;j++)
 99                     ans=min(ans, dp[i][j]);
100         }
101         if(ans==INF)
102             printf("-1\n");
103         else
104             printf("%d\n", ans);
105     }
106     return 0;
107 }