HDU 4280Island Transport（Dinc非STL 模板）

题意： n岛m条路，然后是 n个岛的坐标，然后是m条双向路，包括 岛和 岛 之间 最大客流量，让求 最左边的岛 到右边的岛 最大客流量

分析： 建图 以 左边的岛为原点，最右边的为终点求最大客流量。

刘汝佳STL会超时，因为vector牵扯到 复制操作

然后看大神的将stl全换了 http://www.cnblogs.com/xiao-xin/articles/4452306.html

#include <iostream>
#include <cstring>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <queue>
using namespace std;
const int INF = 0x3f3f3f3f;
const int Max = 100000 + 10;
struct Edge
{
int to, flow, Next;
};
struct Dinic
{
int n, s, t, now;
Edge edges[Max * 2];
bool vis[Max];
int d[Max], head[Max], q[Max];
void init(int _s, int _t, int _n)
{
s = _s; t = _t; n = _n;
memset(head, -1, sizeof(head));
now = 0;
}
void addEdge(int from, int to, int flow)
{
edges[now].to = to; edges[now].flow = flow;
edges[now].Next = head[from]; head[from] = now++;

edges[now].to = from; edges[now].flow = flow;
edges[now].Next = head[to]; head[to] = now++;
}
bool BFS()
{
memset(vis, 0, sizeof(vis));
int Front =0, rear = 0;
q[rear++] = s;
d[s] = 0;
vis[s] = 1;
while (Front < rear)
{
int x = q[Front++];
for (int i = head[x]; i != -1; i = edges[i].Next)
{
if ( vis[edges[i].to] == 0 && edges[i].flow > 0)
{
vis[edges[i].to] = 1;
d[ edges[i].to ] = d[x] + 1;
q[ rear++ ] = edges[i].to;
}
}
}
return vis[t];
}
int DFS(int x, int a)
{
if (x == t || a == 0)
return a;
int flow = 0, f;
for (int i = head[x]; i != -1; i = edges[i].Next)
{
if (d[x] + 1 == d[edges[i].to] && edges[i].flow > 0)
{
f = DFS(edges[i].to, min(a - flow, edges[i].flow));
edges[i].flow -= f;
edges[i ^ 1].flow += f;
flow += f;
if (flow == a)
return flow;
}
}
if (flow == 0)
d[x] = 0;
return flow;
}
int MaxFlow()
{
int flow = 0;
while ( BFS() )
{
flow += DFS(s, INF);
}
return flow;
}

}g;
/*
struct Dinic
{
int n, s, t;
vector<Edge> edges;
vector<int> G[Max];
bool vis[Max];
int d[Max];
int cur[Max];
void init(int _n, int _s, int _t)
{
n = _n;
s = _s;
t = _t;
edges.clear();
for (int i = 0; i <= n; i++)
G[i].clear();
}
void addEdge(int from, int to, int cap)
{
Edge edge;
edge.from = from;
edge.to = to;
edge.cap = cap;
edge.flow = 0;
edges.push_back(edge);
edge.from = to;
edge.to = from;
edge.cap = cap;
edge.flow = 0;
edges.push_back(edge);
int m = (int) edges.size();
G[from].push_back(m - 2);
G[to].push_back(m - 1);
}
bool BFS()
{
memset(vis, 0, sizeof(vis));
queue<int> Q;
Q.push(s);
d[s] = 0;
vis[s] = 1;
while (!Q.empty())
{
int x = Q.front();
Q.pop();
for (int i = 0; i < (int) G[x].size(); i++)
{
Edge & e = edges[ G[x][i] ];
if (!vis[e.to] && e.cap > e.flow)
{
vis[e.to] = 1;
d[e.to] = d[x] + 1;
Q.push(e.to);
}
}
}
return vis[t];
}
int DFS(int x, int a)
{
if (x == t || a == 0)
return a;
int flow = 0, f;
for (int& i = cur[x]; i < (int)G[x].size(); i++)
{
Edge & e = edges[ G[x][i] ];
if (d[x] + 1 == d[e.to] && (f = DFS(e.to,  min(a, e.cap - e.flow))) > 0)
{
e.flow += f;
edges[G[x][i] ^ 1].flow -= f;
flow += f;
a -= f;
if (a == 0)
break;
}
}
return flow;
}
int MaxFlow()
{
int flow = 0;
while( BFS() )
{
memset(cur, 0, sizeof(cur));
flow += DFS(s, INF);
}
return flow;
}

}g;
*/
int main()
{
int T, n, m, east, west;
scanf("%d", &T);
while (T--)
{
scanf("%d%d", &n, &m);
int maxx = -INF, minx = INF;
int x, y, w;
for (int i = 1; i <= n; i++)
{
scanf("%d%d", &x, &y);
if (x > maxx)
{
maxx = x;
west = i;
}
if (x < minx)
{
minx = x;
east = i;
}
}
g.init(east, west, n);
for (int i = 1; i <= m; i++)
{
scanf("%d%d%d", &x, &y, &w);
g.addEdge(x, y, w);
}
printf("%d\n", g.MaxFlow());
}
return 0;
}

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