hdu 3879 方案选择

每日一水～～～

 #include <cstdio>
 #include <cstring>
 #include <vector>
 #define oo 0x3f3f3f3f
 #define N 55010
 using namespace std;

 struct Edge {
     int u, v, f;
     Edge( int u, int v, int f ):u(u),v(v),f(f){}
 };

 int n, m, src, dst;
 vector<Edge> edge;
 vector<int> g[N];
 int dep[N], cur[N], qu[N], bg, ed, idc;
 int sump;

 void init() {
     for( int i=; i<=n+m+; i++ )
         g[i].clear();
     edge.clear();
     sump = ;
     idc = ;
 }
 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];
 }
 int dfs( int u, int a ) {
     if( u==dst || a== ) return a;
     int 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;
 }
 int maxflow() {
     int flow = ;
     while( bfs() ) {
         memset( cur, , sizeof(cur) );
         flow += dfs(src,oo);
     }
     return flow;
 }
 int main() {
     while( scanf( "%d%d", &n, &m )== ) {
         init();
         src = n+m+;
         dst = src+;
         for( int i=,c; i<=n; i++ ) {
             scanf( "%d", &c );
             ++idc;
             adde( idc, dst, c );
         }
         for( int i=,u,v,p; i<=m; i++ ) {
             scanf( "%d%d%d", &u, &v, &p );
             ++idc;
             sump += p;
             adde( src, idc, p );
             adde( idc, u, oo );
             adde( idc, v, oo );
         }
         printf( "%d\n", sump-maxflow() );
     }
 }