hdu 4280 最大流sap

模板套起来

1　　
5 7　　//5个结点，7个边
3 3　　//坐标
3 0　　
3 1
0 0
4 5
1 3 3　　//相连的结点和流
2 3 4
2 4 3
1 5 6
4 5 3
1 4 4
3 4 2

9

 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 using namespace std;
 const int MAXN = ;//点数的最大值
 const int MAXM = ;//边数的最大值
 const int INF = 0x3f3f3f3f;
 int n;
 struct Edge
 {
     int to,next,cap,flow;
 }edge[MAXM];//注意是MAXM
 int tol;
 int head[MAXN];
 int gap[MAXN],dep[MAXN],cur[MAXN];
 void init()
 {
     tol = ;
     memset(head,-,sizeof(head));
 }
 void addedge(int u,int v,int w,int rw = )
 {
     edge[tol].to = v; edge[tol].cap = w; edge[tol].flow = ;
     edge[tol].next = head[u]; head[u] = tol++;
     edge[tol].to = u; edge[tol].cap = rw; edge[tol].flow = ;
     edge[tol].next = head[v]; head[v] = tol++;
 }
 int Q[MAXN];
 void BFS(int start,int end)
 {
     memset(dep,-,sizeof(dep));
     memset(gap,,sizeof(gap));
     gap[] = ;
     int front = , rear = ;
     dep[end] = ;
     Q[rear++] = end;
     while(front != rear)
     {
         int u = Q[front++];
         for(int i = head[u]; i != -; i = edge[i].next)
         {
             int v = edge[i].to;
             if(dep[v] != -)continue;
             Q[rear++] = v;
             dep[v] = dep[u] + ;
             gap[dep[v]]++;
         }
     }
 }
 int S[MAXN];
 int SAP(int start,int end,int N)
 {
     BFS(start,end);
     memcpy(cur,head,sizeof(head));
     int top = ;
     int u = start;
     int ans = ;
     while(dep[start] < N)
     {
         if(u == end)
         {
             int Min = INF;
             int inser;
             for(int i = ;i < top;i++)
             if(Min > edge[S[i]].cap - edge[S[i]].flow)
             {
                 Min = edge[S[i]].cap - edge[S[i]].flow;
                 inser = i;
             }
             for(int i = ;i < top;i++)
             {
                 edge[S[i]].flow += Min;
                 edge[S[i]^].flow -= Min;
             }
             ans += Min;
             top = inser;
             u = edge[S[top]^].to;
             continue;
         }
         bool flag = false;
         int v;
         for(int i = cur[u]; i != -; i = edge[i].next)
         {
             v = edge[i].to;
             if(edge[i].cap - edge[i].flow && dep[v]+ == dep[u])
             {
                 flag = true;
                 cur[u] = i;
                 break;
             }
         }
         if(flag)
         {
             S[top++] = cur[u];
             u = v;
             continue;
         }
         int Min = N;
         for(int i = head[u]; i != -; i = edge[i].next)
         if(edge[i].cap - edge[i].flow && dep[edge[i].to] < Min)
         {
             Min = dep[edge[i].to];
             cur[u] = i;
         }
         gap[dep[u]]--;
         if(!gap[dep[u]])return ans;
         dep[u] = Min + ;
         gap[dep[u]]++;
         if(u != start)u = edge[S[--top]^].to;
         }
     return ans;
 }
 int main()
 {
     #ifndef ONLINE_JUDGE
     freopen("1.in","r",stdin);
     #endif
     int start,end;
     int m;
     int u,v,z;
     int T;
     scanf("%d",&T);
     while(T--)
     {
         init();
         scanf("%d%d",&n,&m);
         int minx=;
         int maxx=-;
         int x,y;
         for(int i=;i<=n;i++)
         {
             scanf("%d%d",&x,&y);
             if(minx>x)
             {
                 minx=x;
                 start=i;
             }
             if(maxx<x)
             {
                 maxx=x;
                 end=i;
             }
         }
         while(m--)
         {
             scanf("%d%d%d",&u,&v,&z);
             addedge(u,v,z);
             addedge(v,u,z);
         }
         int ans=SAP(start,end,n);
         printf("%d\n",ans);
     }
     return ;
 }