BZOJ 2157 旅行

裸链剖。

这大概是我第一份两百行左右的代码吧。

然而我把题看错了233333333调了将近两天。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxv 100050
#define maxe 300050
using namespace std;
struct edge
{
    int v,w,nxt;
}e[maxe];
struct edge_
{
    int u,v,w;
}eg[maxe];
char s[];
int n,x,y,z,g[maxv],nume=,nume_=,m;
int dis[maxv],w[maxv],top[maxv],fath[maxv],size[maxv],son[maxv],cnt=,tot=,c[maxv];
int ls[maxv<<],rs[maxv<<],lazy[maxv<<],sum[maxv<<],mx[maxv<<],mn[maxv<<],root;
void addedge(int u,int v,int w)
{
    e[++nume].v=v;
    e[nume].w=w;
    e[nume].nxt=g[u];
    g[u]=nume;
}
void addedge_(int u,int v,int w)
{
    eg[++nume_].u=u;
    eg[nume_].v=v;
    eg[nume_].w=w;
}
void dfs1(int x,int father)
{
    size[x]=;son[x]=;
    for (int i=g[x];i;i=e[i].nxt)
    {
        int v=e[i].v;
        if (v!=father)
        {
            fath[v]=x;dis[v]=dis[x]+;
            dfs1(v,x);
            size[x]+=size[v];
            if (size[v]>size[son[x]]) son[x]=v;
        }
    }
}
void dfs2(int x,int father)
{
    top[x]=father;w[x]=++cnt;
    if (son[x]!=) dfs2(son[x],father);
    for (int i=g[x];i;i=e[i].nxt)
    {
        int v=e[i].v;
        if (v!=fath[x])
        {
            if (v!=son[x]) dfs2(v,v);
            c[w[v]]=e[i].w;
        }
    }
}
void pushup(int now)
{
    sum[now]=sum[ls[now]]+sum[rs[now]];
    mx[now]=max(mx[ls[now]],mx[rs[now]]);
    mn[now]=min(mn[ls[now]],mn[rs[now]]);
}
void build(int &now,int left,int right)
{
    now=++tot;lazy[now]=;
    if (left==right)
    {
        sum[now]=mn[now]=mx[now]=c[left];
        return;
    }
    int mid=(left+right)>>;
    build(ls[now],left,mid);
    build(rs[now],mid+,right);
    pushup(now);
}
void pushdown(int now,int left,int right)
{
    int r1,r2;
    if (lazy[now]==)
    {
        sum[ls[now]]=-sum[ls[now]];sum[rs[now]]=-sum[rs[now]];
        r1=mn[ls[now]];r2=mx[ls[now]];mn[ls[now]]=-r2;mx[ls[now]]=-r1;
        r1=mn[rs[now]];r2=mx[rs[now]];mn[rs[now]]=-r2;mx[rs[now]]=-r1;
        lazy[ls[now]]^=;lazy[rs[now]]^=;
        lazy[now]=;
    }
}
void modify(int now,int left,int right,int l,int r,int p,int type)
{
    pushdown(now,left,right);
    if ((left==l) && (right==r))
    {
        if (type==)
        {
            sum[now]=p;
            mx[now]=p;mn[now]=p;
            return;
        }
        else
        {
            lazy[now]^=;
            sum[now]=-sum[now];
            int r1,r2;r1=mn[now];r2=mx[now];
            mn[now]=-r2;mx[now]=-r1;
            return;
        }
    }
    int mid=(left+right)>>;
    if (r<=mid) modify(ls[now],left,mid,l,r,p,type);
    else if (l>=mid+) modify(rs[now],mid+,right,l,r,p,type);
    else
    {
        modify(ls[now],left,mid,l,mid,p,type);
        modify(rs[now],mid+,right,mid+,r,p,type);
    }
    pushup(now);
}
int ask(int now,int left,int right,int l,int r,int type)
{
    pushdown(now,left,right);
    if ((left==l) && (right==r))
    {
        if (type==) return sum[now];
        else if (type==) return mx[now];
        else return mn[now];
    }
    int mid=(left+right)>>;
    if (r<=mid) return ask(ls[now],left,mid,l,r,type);
    else if (l>=mid+) return ask(rs[now],mid+,right,l,r,type);
    else
    {
        if (type==) return ask(ls[now],left,mid,l,mid,type)+ask(rs[now],mid+,right,mid+,r,type);
        else if (type==) return max(ask(ls[now],left,mid,l,mid,type),ask(rs[now],mid+,right,mid+,r,type));
        else return min(ask(ls[now],left,mid,l,mid,type),ask(rs[now],mid+,right,mid+,r,type));
    }
}
void work()
{
    scanf("%d%d",&x,&y);
    x++;y++;
    int f1=top[x],f2=top[y];
    if (s[]=='N')
    {
        while (f1!=f2)
        {
            if (dis[f1]<dis[f2]) {swap(f1,f2);swap(x,y);}
            modify(root,,cnt,w[f1],w[x],,);
            x=fath[f1];f1=top[x];
        }
        if (x!=y)
        {
            if (dis[x]>dis[y]) swap(x,y);
            modify(root,,cnt,w[son[x]],w[y],,);
        }
    }
    else if (s[]=='S')
    {
        int ans=;
        while (f1!=f2)
        {
            if (dis[f1]<dis[f2]) {swap(f1,f2);swap(x,y);}
            ans+=ask(root,,cnt,w[f1],w[x],);
            x=fath[f1];f1=top[x];
        }
        if (x!=y)
        {
            if (dis[x]>dis[y]) swap(x,y);
            ans+=ask(root,,cnt,w[son[x]],w[y],);
        }
        printf("%d\n",ans);
    }
    else if ((s[]=='M') && (s[]=='A'))
    {
        int ans=0xefefefef;
        while (f1!=f2)
        {
            if (dis[f1]<dis[f2]) {swap(f1,f2);swap(x,y);}
            ans=max(ans,ask(root,,cnt,w[f1],w[x],));
            x=fath[f1];f1=top[x];
        }
        if (x!=y)
        {
            if (dis[x]>dis[y]) swap(x,y);
            ans=max(ans,ask(root,,cnt,w[son[x]],w[y],));
        }
        printf("%d\n",ans);
    }
    else
    {
        int ans=0x3f3f3f3f;
        while (f1!=f2)
        {
            if (dis[f1]<dis[f2]) {swap(f1,f2);swap(x,y);}
            ans=min(ans,ask(root,,cnt,w[f1],w[x],));
            x=fath[f1];f1=top[x];
        }
        if (x!=y)
        {
            if (dis[x]>dis[y]) swap(x,y);
            ans=min(ans,ask(root,,cnt,w[son[x]],w[y],));
        }
        printf("%d\n",ans);
    }
}
int main()
{
    scanf("%d",&n);
    for (int i=;i<=n-;i++)
    {
        scanf("%d%d%d",&x,&y,&z);
        x++;y++;
        addedge(x,y,z);
        addedge(y,x,z);
        addedge_(x,y,z);
    }
    dfs1(,);
    dfs2(,);
    build(root,,cnt);
    scanf("%d",&m);
    for (int i=;i<=m;i++)
    {
        scanf("%s",s);
        if (s[]=='C')
        {
            scanf("%d%d",&x,&y);
            int u,v;
            u=eg[x].u;v=eg[x].v;
            if (fath[u]==v) modify(root,,cnt,w[u],w[u],y,);
            else modify(root,,cnt,w[v],w[v],y,);
        }
        else work();
    }
    return ;
}