bzoj 3931 最短路+最大流

较水，但因为范围问题WA了两次。。。。

 /**************************************************************
     Problem: 3931
     User: idy002
     Language: C++
     Result: Accepted
     Time:392 ms
     Memory:3224 kb
 ****************************************************************/

 #include <cstdio>
 #include <cstring>
 #include <vector>
 #include <queue>
 #define min(a,b) ((a)<(b)?(a):(b))
 #define N 1100
 #define M 200010
 #define oo 0x3f3f3f3f
 using namespace std;

 typedef long long dnt;
 struct Pair {
     int u;
     dnt d;
     Pair( int u, dnt d ):u(u),d(d){}
     bool operator<( const Pair &p ) const { return d>p.d; }
 };
 struct Edge {
     int u, v, f;
     Edge( int u, int v, int f ):u(u),v(v),f(f){}
 };
 struct Dinic {
     int src, dst;
     vector<Edge> edge;
     vector<int> g[N];
     int dep[N], cur[N], qu[N], bg, ed;
     void init( int src, int dst ) {
         this->src = src;
         this->dst = dst;
     }
     void adde( int u, int v, int f ) {
         g[u].push_back( edge.size() );
         edge.push_back( Edge(u,v,f) );
         g[v].push_back( edge.size() );
         edge.push_back( Edge(v,u,) );
     }
     bool bfs() {
         memset( dep, , sizeof(dep) );
         qu[bg=ed=] = src;
         dep[src] = ;
         while( bg<=ed ) {
             int u=qu[bg++];
             for( int t=; t<g[u].size(); t++ )  {
                 Edge &e = edge[g[u][t]];
                 if( e.f && !dep[e.v] ) {
                     dep[e.v] = dep[e.u]+;
                     qu[++ed] = e.v;
                 }
             }
         }
         return dep[dst];
     }
     dnt dfs( int u, dnt a ) {
         if( u==dst || a== ) return a;
         dnt remain=a, past=, na;
         for( int &t=cur[u]; t<g[u].size(); t++ ) {
             Edge &e = edge[g[u][t]];
             Edge &ve = edge[g[u][t]^];
             if( e.f && dep[e.v]==dep[e.u]+ && (na=dfs(e.v,min(remain,e.f))) ) {
                 remain -= na;
                 past += na;
                 e.f -= na;
                 ve.f += na;
                 if( !remain ) break;
             }
         }
         return past;
     }
     dnt maxflow() {
         dnt rt = ;
         while( bfs() ) {
             memset( cur, , sizeof(cur) );
             rt += dfs(src,0x3f3f3f3f3f3f3f3fll);
         }
         return rt;
     }
 }D;

 int n, m;
 int head[N], cc[N], dest[M], wght[M], next[M], etot;
 dnt dis[][N];
 int in[N], out[N], src, dst, idc;

 void adde( int u, int v, int w ) {
     etot++;
     dest[etot] = v;
     wght[etot] = w;
     next[etot] = head[u];
     head[u] = etot;
 }
 void dijstra( int src, dnt dis[] ) {
     static bool done[N];
     memset( done, false, sizeof(done) );
     priority_queue<Pair> q;
     q.push( Pair(src,) );
     dis[src] = ;
     while( !q.empty() ) {
         Pair p = q.top();
         q.pop();
         int u=p.u;
         if( done[u] ) continue;
         done[u] = true;
         for( int t=head[u]; t; t=next[t] ) {
             int v=dest[t], w=wght[t];
             if( dis[v]>dis[u]+w ) {
                 dis[v]=dis[u]+w;
                 q.push( Pair(v,dis[v]) );
             }
         }
     }
 }
 void makeid() {
     idc = ;
     for( int i=; i<=n; i++ ) {
         in[i] = ++idc;
         out[i] = ++idc;
     }
     src = out[];
     dst = in[n];
 }
 void build() {
     memset( dis, 0x3f, sizeof(dis) );
     dijstra( , dis[] );
     dijstra( n, dis[] );
     makeid();
     D.init( src, dst );
     for( int i=; i<=n; i++ )
         if( dis[][n]==dis[][i]+dis[][i] )
             D.adde( in[i], out[i], cc[i] );
     for( int u=; u<=n; u++ )
         for( int t=head[u]; t; t=next[t] ) {
             int v=dest[t], w=wght[t];
             if( dis[][u]+dis[][v]+w==dis[][n] )
                 D.adde( out[u], in[v], oo );
         }
 }
 int main() {
     scanf( "%d%d", &n, &m );
     for( int i=,u,v,w; i<=m; i++ ) {
         scanf( "%d%d%d", &u, &v, &w );
         adde( u, v, w );
         adde( v, u, w );
     }
     for( int i=; i<=n; i++ )
         scanf( "%d", cc+i );
     build();
     printf( "%lld\n", D.maxflow() );
 }