Island Transport 【HDU - 4280】【最大流Dinic】

题目链接

可以说是真的把时间卡爆了，不断的修改了好多次之后才A了，一直T一直T，哭了……

可以说是很练时间优化了，不断的改，不断的提交，最后竟然是改了Dinic中的BFS()中，我们一旦搜索到了T之后就是直接break掉，就可以过了。还有一个优化就是在Dinic上面需要加当前弧优化操作才可以，另外不知道改出来的手动队列到最后有没有派上用处。

 #pragma comment(linker, "/STACK:1024000000,1024000000")
 #include <iostream>
 #include <cstdio>
 #include <cmath>
 #include <string>
 #include <cstring>
 #include <algorithm>
 #include <limits>
 #include <vector>
 #include <stack>
 #include <queue>
 #include <set>
 #include <map>
 #define lowbit(x) ( x&(-x) )
 #define pi 3.141592653589793
 #define e 2.718281828459045
 #define INF 0x3f3f3f3f
 #define HalF (l + r)>>1
 #define lsn rt<<1
 #define rsn rt<<1|1
 #define Lson lsn, l, mid
 #define Rson rsn, mid+1, r
 #define QL Lson, ql, qr
 #define QR Rson, ql, qr
 #define myself rt, l, r
 using namespace std;
 typedef unsigned long long ull;
 typedef long long ll;
 const int maxN = 1e5 + ;
 int N, M, S, T, head[maxN], cnt, cur[maxN];
 struct Eddge
 {
     int nex, to, flow;
     Eddge(int a=-, int b=, int c=):nex(a), to(b), flow(c) {}
 }edge[maxN<<];
 inline void addEddge(int u, int v, int flow)
 {
     edge[cnt] = Eddge(head[u], v, flow);
     head[u] = cnt++;
 }
 inline void _add(int u, int v, int flow) { addEddge(u, v, flow); addEddge(v, u, ); }
 int deep[maxN];
 int Q[maxN<<], top, tail;
 bool bfs()
 {
     for(int i=; i<=N; i++) deep[i] = ;
     deep[S] = ;
     top = tail = ;
     Q[++top] = S;
     while(tail < top)
     {
         int u = Q[++tail];
         if(u == T) break;
         for(int i=head[u], v, f; ~i; i=edge[i].nex)
         {
             v = edge[i].to; f = edge[i].flow;
             if(f >  && !deep[v])
             {
                 deep[v] = deep[u] + ;
                 Q[++top] = v;
             }
         }
     }
     return deep[T];
 }
 int dfs(int u, int dist)
 {
     if(u == T) return dist;
     for(int &i=cur[u], v, f; ~i; i=edge[i].nex)
     {
         v = edge[i].to; f = edge[i].flow;
         if(deep[v] == deep[u] +  && f > )
         {
             int di = dfs(v, min(dist, f));
             if(di)
             {
                 edge[i].flow -= di;
                 edge[i^].flow += di;
                 return di;
             }
         }
     }
     return ;
 }
 int Dinic()
 {
     int ans = , tmp;
     while(bfs())
     {
         for(int i=; i<=N; i++) cur[i] = head[i];
         while((tmp = dfs(S, INF))) ans += tmp;
     }
     return ans;
 }
 inline void init()
 {
     cnt = ;
     for(int i=; i<=N; i++) head[i] = -;
 }
 int main()
 {
     int Cas;  scanf("%d", &Cas);
     while(Cas--)
     {
         scanf("%d%d", &N, &M);
         init();
         int minn = INF, maxx = -INF;
         for(int i=, x, y; i<=N; i++)
         {
             scanf("%d%d", &x, &y);
             if(x < minn)
             {
                 minn = x;
                 S = i;
             }
             if(x > maxx)
             {
                 maxx = x;
                 T = i;
             }
         }
         for(int i=, u, v, w; i<=M; i++)
         {
             scanf("%d%d%d", &u, &v, &w);
             //_add(u, v, w);
             //_add(v, u, w);
             addEddge(u, v, w);
             addEddge(v, u, w);
         }
         printf("%d\n", Dinic());
     }
     return ;
 }