BZOJ 2286 消耗战

Posted 2020-08-06 ziliuziliu

虚树裸题。

23333以后memset千万慎用。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxv 250050
#define maxe 500050
#define inf 0x7f7f7f7f7f7f7f7fLL
using namespace std;
struct edge
{
    long long v,w,nxt;
}e[maxe],tr[maxe<<2];
struct ask
{
    long long pnt,dfn;
}q[maxv];
using namespace std;
long long n,x,y,z,g[maxv],nume=0,numt=0,gt[maxv],dfn[maxv],dis[maxv],anc[maxv][24],mn[maxv][24],dep[maxv];
long long m,k,stack[maxv],top=0,times=0,val[maxv],hash[maxv],now_cnt,fath[maxv],laste=0;
long long read()
{
    long long data=0;char ch;
    while (ch<‘0‘ || ch>‘9‘) ch=getchar();
    do
    {
        data=data*10+ch-‘0‘;
        ch=getchar();
    }while (ch>=‘0‘ && ch<=‘9‘);
    return data;
}
bool cmp(ask x,ask y)
{
    return x.dfn<y.dfn;
}
void addedge(long long u,long long v,long long w)
{
    e[++nume].v=v;
    e[nume].w=w;
    e[nume].nxt=g[u];
    g[u]=nume;
}
void addtree(long long u,long long v,long long w)
{
    tr[++numt].v=v;
    tr[numt].w=w;
    if (gt[u]<=laste) tr[numt].nxt=0;
    else tr[numt].nxt=gt[u];
    gt[u]=numt;
}
void dfs(long long x)
{
    dfn[x]=++times;
    for (long long i=g[x];i;i=e[i].nxt)
    {
        long long v=e[i].v;
        if (v!=anc[x][0])
        {
            anc[v][0]=x;mn[v][0]=e[i].w;dis[v]=dis[x]+e[i].w;
            dep[v]=dep[x]+1;
            dfs(v);
        }
    }
}
void get_table()
{
    for (long long e=1;e<=22;e++)
        for (long long i=1;i<=n;i++)
        {
            anc[i][e]=anc[anc[i][e-1]][e-1];
            mn[i][e]=min(mn[i][e-1],mn[anc[i][e-1]][e-1]);
        }
}
void reset()
{
    top=0;
}
long long lca(long long x,long long y)
{
    if (dep[x]<dep[y]) swap(x,y);
    for (long long e=22;e>=0;e--)
    {
        if ((dep[anc[x][e]]>=dep[y]) && (anc[x][e]))
            x=anc[x][e];    
    }    
    if (x==y) return x;
    for (long long e=22;e>=0;e--)
    {
        if (anc[x][e]!=anc[y][e])
        {
            x=anc[x][e];
            y=anc[y][e];
        }
    }
    return anc[x][0];
}
long long ask(long long x,long long y)
{
    long long ret=inf;
    for (long long e=22;e>=0;e--)
    {
        if ((dep[anc[x][e]]>=dep[y]) && (anc[x][e]))
        {
            ret=min(ret,mn[x][e]);
            x=anc[x][e];
        }
    }
    return ret;
}
void dp(long long x)
{
    val[x]=0;
    for (long long i=gt[x];i;i=tr[i].nxt)
    {
        long long v=tr[i].v;
        if (v!=fath[x])
        {
            dp(v);
            if (hash[v]==now_cnt) val[x]+=tr[i].w;
            else val[x]+=min(val[v],tr[i].w);
        }
    }
}
void work()
{
    k=read();
    for (long long i=1;i<=k;i++)
    {
        x=read();
        q[i].pnt=x;q[i].dfn=dfn[x];
        hash[x]=now_cnt;
    }
    sort(q+1,q+k+1,cmp);
    stack[++top]=1;
    for (long long i=1;i<=k;i++)
    {
        long long x=q[i].pnt,fr=stack[top],se=stack[top-1];
        long long t=lca(x,fr);
        if (t==fr) stack[++top]=x;
        else
        {
            for (;;)
            {
                long long ret;
                fr=stack[top];se=stack[top-1];
                long long t=lca(x,fr);
                if (dfn[t]<dfn[se]) {ret=ask(fr,se);addtree(fr,se,ret);addtree(se,fr,ret);fath[fr]=se;top--;}
                else if (dfn[t]==dfn[se]) {ret=ask(fr,se);addtree(fr,se,ret);addtree(se,fr,ret);fath[fr]=se;top--;break;}
                else 
                {
                    long long ret=ask(fr,t);
                    addtree(fr,t,ret);addtree(t,fr,ret);
                    stack[top]=t;fath[fr]=t;break;
                }
            }
            stack[++top]=x;
        }    
    }
    while (top>=2)
    {
        long long fr=stack[top],se=stack[top-1],ret=ask(fr,se);
        addtree(fr,se,ret);
        addtree(se,fr,ret);
        fath[fr]=se;
        top--;
    }
    dp(1);printf("%lld\n",val[1]);
    laste=numt;
    return;
}
int main()
{
    n=read();
    for (long long i=1;i<=n-1;i++)
    {
        x=read();y=read();z=read();
        addedge(x,y,z);addedge(y,x,z);
    }
    dfs(1);
    get_table();
    m=read();
    for (long long i=1;i<=m;i++)
    {
        reset();
        now_cnt=i;
        work();
    }
    return 0;
}