[Network stream] [update TEMPLATE] dinic multi-channel augmented + current arc

Add Current Arc Optimization

#define INF (1<<30)#define N 101000#define M 200010#pragma comment(linker, "/STACK:32000000")int n,m,s,t;int head[N],cur[N],cnt;struct edge{    int v,w,next;}e[M];int q[N],dis[N],start,end;void addedge(int u,int v,int w){e[cnt]=(edge){v,w,head[u]}; head[u]=cnt++;e[cnt]=(edge){u,0,head[v]}; head[v]=cnt++;}int bfs(){    memset(dis,-1,sizeof(dis));    start=end=0; q[0]=t; dis[t]=0;    while (start<=end)    {        int u=q[start++];        for(int i=head[u];i!=-1;i=e[i].next)        if(dis[e[i].v]==-1 && e[i^1].w>0){  dis[e[i].v]=dis[u]+1; q[++end]=e[i].v;  }    }    return dis[s]!=-1;}int dfs(int u,int t,int flow){    if(u==t) return flow;    int delta=flow;    for(int &i=cur[u];i!=-1;i=e[i].next)        if(dis[u]==dis[e[i].v]+1 && e[i].w>0)        {            int d=dfs(e[i].v,t,min(delta,e[i].w));            e[i].w-=d;    e[i^1].w+=d;   delta-=d;            if(delta==0) break;        }    return flow-delta;}int ans0=0;while (bfs()){for(int i=1;i<=n;i++) cur[i]=head[i];ans0+=dfs(s,t,INF);}

The speed is strange. POJ3469 is slower than the previous pre-stream push, but the HDU4280 can speed up to 4000 +. Because it is recursive, pay attention to stack explosion.