BZOJ1097: [POI2007]旅游景点atr

 1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<cmath>
 4 #include<cstring>
 5 #include<algorithm>
 6 #include<iostream>
 7 #include<vector>
 8 #include<map>
 9 #include<set>
10 #include<queue>
11 #include<string>
12 #define inf 1000000000
13 #define maxn 50000
14 #define maxm 500000
15 #define eps 1e-10
16 #define ll long long
17 #define pa pair<int,int>
18 #define for0(i,n) for(int i=0;i<=(n);i++)
19 #define for1(i,n) for(int i=1;i<=(n);i++)
20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
21 using namespace std;
22 inline int read()
23 {
24     int x=0,f=1;char ch=getchar();
25     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
26     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
27     return x*f;
28 }
29 struct edge{int go,next,w;}e[2*maxm];
30 int n,m,k,tot,a[25],q[maxn],d[25][maxn],head[maxn],dp[22][1<<21];
31 bool v[maxn];
32 inline void ins(int x,int y,int z)
33 {
34     e[++tot].go=y;e[tot].w=z;e[tot].next=head[x];head[x]=tot;
35 }
36 inline void insert(int x,int y,int z)
37 {
38     ins(x,y,z);ins(y,x,z);
39 }
40 inline void spfa(int s)
41 {
42     for(int i=0;i<n;++i) d[s][i]=inf;
43     memset(v,0,sizeof(v));
44     int l=0,r=1,x,y;q[1]=s;d[s][s]=0;
45     while(l!=r)
46     {
47         x=q[++l];if(l==maxn)l=0;v[x]=0;
48         for(int i=head[x];i;i=e[i].next)
49          if(d[s][x]+e[i].w<d[s][y=e[i].go])
50          {
51              d[s][y]=d[s][x]+e[i].w;
52              if(!v[y]){v[y]=1;q[++r]=y;if(r==maxn)r=0;}
53          }
54     }
55 }
56 inline int dfs(int x,int y)
57 {
58     if(dp[x][y]>=0)return dp[x][y];
59     if(y==(1<<k)-1)return d[x][n-1];
60     dp[x][y]=inf;
61     for1(i,k)
62      if((y&a[i])==a[i])
63       dp[x][y]=min(dp[x][y],d[x][i]+dfs(i,y|(1<<(i-1))));
64     return dp[x][y];  
65 }
66 int main()
67 {
68     freopen("input.txt","r",stdin);
69     freopen("output.txt","w",stdout);
70     n=read();m=read();k=read();
71     int x,y,z;
72     for1(i,m)x=read()-1,y=read()-1,z=read(),insert(x,y,z);
73     for0(i,k)spfa(i);
74     m=read();
75     memset(dp,-1,sizeof(dp));
76     for1(i,m)x=read()-1,y=read()-1,a[y]|=1<<(x-1);
77     printf("%d\n",dfs(0,0));
78     return 0;
79 }

 1 #include<cstdio>
 2 #include<queue>
 3 #include<vector>
 4 #include<algorithm>
 5 #include<cstring>
 6 #include<iostream>
 7 using namespace std;
 8 #define N 30000
 9 #define M 500000
10 struct node{
11     int w,u;
12     bool operator<(const node&rhs)const{
13         return w>rhs.w;
14     }
15 };priority_queue<node>Q;
16 int to[M],mm=0,G[N],wei[M],nex[M];
17 void addedge(int u,int v,int w)
18 {
19     nex[mm]=G[u];G[u]=mm;wei[mm]=w;to[mm]=v;mm++;
20 }
21 int dis[N],n,m,k,depend[30],d[30][30],dp[1<<20][21];
22 void shortest(int S)
23 {
24     for(int i=0;i<=n;i++)dis[i]=~0U>>3;
25     dis[S]=0;Q.push((node){0,S});
26     while(!Q.empty())
27     {
28         int u=Q.top().u;Q.pop();
29         for(int i=G[u];~i;i=nex[i])
30         {
31             int v=to[i];
32             if(dis[v]>dis[u]+wei[i])
33             {
34                 dis[v]=wei[i]+dis[u];
35                 Q.push((node){dis[v],v});
36             }
37         }
38     }
39 }
40 bool check(int state,int kth)
41 {
42     return (state&depend[kth])==depend[kth];
43 }
44 int dfs(int state,int now)
45 {
46     if(dp[state][now]>=0)return dp[state][now];
47     if(state==(1<<k)-1)return d[now][k+1];
48     dp[state][now]=~0U>>3;
49     for(int i=1;i<=k;i++)
50         if(check(state,i-1)){
51             dp[state][now]=min(dp[state][now],dfs(state|(1<<(i-1)),i)+d[now][i]);
52         }    
53     return dp[state][now];
54 }
55 int main(){
56     freopen("input.txt","r",stdin);
57     freopen("output.txt","w",stdout);
58     memset(G,-1,sizeof(G));
59     scanf("%d%d%d",&n,&m,&k);
60     for(int i=1,a,b,c;i<=m;i++)
61     {
62         scanf("%d%d%d",&a,&b,&c);
63         a--;
64         b--;
65         addedge(a,b,c);
66         addedge(b,a,c);
67     }scanf("%d",&m);
68     for(int i=1,a,b;i<=m;i++)
69     {
70         scanf("%d%d",&a,&b);
71         a-=2;b-=2;
72         depend[b]|=(1<<a);
73     }for(int i=0;i<=k;i++)
74     {
75         shortest(i);
76         for(int j=0;j<=k;j++)d[i][j]=dis[j];
77         d[i][k+1]=dis[n-1];
78     }
79     memset(dp,-1,sizeof(dp));
80     printf("%d\n",dfs(0,0));
81 }