网络最大流增广路模板(EK & Dinic)

int fir[maxn];
int u[maxm],v[maxm],cap[maxm],flow[maxm],nex[maxm];
int e_max;
int p[maxn],q[maxn],d[maxn];

void add_edge(int _u,int _v,int _w)
{
int e;
e=e_max++;
u[e]=_u;v[e]=_v;cap[e]=_w;
nex[e]=fir[u[e]];fir[u[e]]=e;
e=e_max++;
u[e]=_v;v[e]=_u;cap[e]=0;
nex[e]=fir[u[e]];fir[u[e]]=e;
}

int max_flow(int s,int t)
{
memset(flow,0,sizeof flow);
int total_flow=0;

for (;;)
{
memset(d,0,sizeof d);
d[s]=INF;
int f=0,r=0;
q[0]=s;
while (f<=r)
{
int _u=q[f++];
for (int e=fir[_u];~e;e=nex[e])
{
if (!d[v[e]] && cap[e]>flow[e])
{
q[++r]=v[e];
p[v[e]]=e;
d[v[e]]=min(d[u[e]],cap[e]-flow[e]);
}
}
}

if (d[t]==0) break;

for (int e=p[t];;e=p[u[e]])
{
flow[e]+=d[t];
flow[e^1]-=d[t];
if (u[e]==s) break;
}

total_flow+=d[t];
}

return total_flow;
}

int fir[maxn];
int u[maxm],v[maxm],cap[maxm],flow[maxm],nex[maxm];
int e_max;
int iter[maxn],q[maxn],lv[maxn];

void add_edge(int _u,int _v,int _w)
{
int e;
e=e_max++;
u[e]=_u;v[e]=_v;cap[e]=_w;
nex[e]=fir[u[e]];fir[u[e]]=e;
e=e_max++;
u[e]=_v;v[e]=_u;cap[e]=0;
nex[e]=fir[u[e]];fir[u[e]]=e;
}

void dinic_bfs(int s)
{
int f,r;
memset(lv,-1,sizeof lv);
q[f=r=0]=s;
lv[s]=0;
while(f<=r)
{
int x=q[f++];
for (int e=fir[x];~e;e=nex[e])
{
if (cap[e]>flow[e] && lv[v[e]]<0)
{
lv[v[e]]=lv[u[e]]+1;
q[++r]=v[e];
}
}
}
}

int dinic_dfs(int _u,int t,int _f)
{
if (_u==t)  return _f;
for (int &e=iter[_u];~e;e=nex[e])
{
if (cap[e]>flow[e] && lv[_u]<lv[v[e]])
{
int _d=dinic_dfs(v[e],t,min(_f,cap[e]-flow[e]));
if (_d>0)
{
flow[e]+=_d;
flow[e^1]-=_d;
return _d;
}
}
}

return 0;
}

int max_flow(int s,int t)
{

memset(flow,0,sizeof flow);
int total_flow=0;

for (;;)
{
dinic_bfs(s);
if (lv[t]<0)    return total_flow;
memcpy(iter,fir,sizeof iter);
int _f;

while ((_f=dinic_dfs(s,t,INF))>0)
total_flow+=_f;
}

return total_flow;
}