树链剖分【p3038】[USACO11DEC]牧草种植Grass Planting

表示看不太清.

概括题意

树上维护区间修改与区间和查询.

很明显树剖裸题,切掉,细节处错误T了好久 TAT

代码

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#define int long long
#define R register
#define ls o<<1
#define rs o<<1|1
#define N 500008
using namespace std;
inline void in(int &x)
{
    int f=1;x=0;char s=getchar();
    while(!isdigit(s)){if(s=='-')f=-1;s=getchar();}
    while(isdigit(s)){x=x*10+s-'0';s=getchar();}
    x*=f;
}
int n,m,head[N],tot,f[N],son[N],size[N],depth[N];
struct cod{int u,v;}edge[N<<2];
inline void add(int x,int y)
{
    edge[++tot].u=head[x];
    edge[tot].v=y;
    head[x]=tot;
}
void dfs1(int u,int fa)
{
    f[u]=fa;depth[u]=depth[fa]+1;size[u]=1;
    for(R int i=head[u];i;i=edge[i].u)
    {
        if(edge[i].v==fa)continue;
        dfs1(edge[i].v,u);
        size[u]+=size[edge[i].v];
        if(son[u]==-1 or size[son[u]]<size[edge[i].v])
            son[u]=edge[i].v;
    }
}
int idx,dfn[N],fdfn[N],top[N];
void dfs2(int u,int t)
{
    top[u]=t;dfn[u]=++idx;fdfn[idx]=u;
    if(son[u]==-1)return;
    dfs2(son[u],t);
    for(R int i=head[u];i;i=edge[i].u)
    {
        if(dfn[edge[i].v])continue;
        dfs2(edge[i].v,edge[i].v);
    }
}
int tr[N<<2],tg[N<<2],a[N];
inline void up(int o){tr[o]=tr[ls]+tr[rs];}
inline void down(int o,int l,int r)
{
    if(tg[o])
    {
        int mid=(l+r)>>1;
        tg[ls]+=tg[o];tg[rs]+=tg[o];
        tr[ls]+=(mid-l+1)*tg[o];
        tr[rs]+=(r-mid)*tg[o];
        tg[o]=0;
    }
}
void change(int o,int l,int r,int x,int y,int z)
{
    if(x<=l and y>=r)
    {
        tr[o]+=(r-l+1)*z;
        tg[o]+=z;
        return;
    }
    down(o,l,r);
    int mid=(l+r)>>1;
    if(x<=mid)change(ls,l,mid,x,y,z);
    if(y>mid)change(rs,mid+1,r,x,y,z);
    up(o);
}
int query(int o,int l,int r,int x,int y)
{
    if(x<=l and y>=r)return tr[o];
    down(o,l,r);
    int mid=(l+r)>>1,res=0;
    if(x<=mid)res+=query(ls,l,mid,x,y);
    if(y>mid)res+=query(rs,mid+1,r,x,y);
    return res;
}
inline void tchange(int x,int y,int z)
{
    int fx=top[x],fy=top[y];
    while(fx!=fy)
    {
        if(depth[fx]>depth[fy])
        {
            change(1,1,idx,dfn[fx],dfn[x],z);
            x=f[fx];
        }
        else
        {
            change(1,1,idx,dfn[fy],dfn[y],z);
            y=f[fy];
        }
        fx=top[x],fy=top[y];
    }
    if(x==y)return;
    if(dfn[x]>dfn[y])swap(x,y);
    change(1,1,idx,dfn[x]+1,dfn[y],z);
}
inline int tquery(int x,int y)
{
    int fx=top[x],fy=top[y],res=0;
    while(fx!=fy)
    {
        if(depth[fx]>depth[fy])
        {
            res+=query(1,1,idx,dfn[fx],dfn[x]);
            x=f[fx];
        }
        else
        {
            res+=query(1,1,idx,dfn[fy],dfn[y]);
            y=f[fy];
        }
        fx=top[x],fy=top[y];
    }
    if(x==y)return res;
    if(dfn[x]>dfn[y])swap(x,y);
    res+=query(1,1,idx,dfn[x]+1,dfn[y]);
    return res;
}
char s[10];
signed main()
{
    in(n),in(m);memset(son,-1,sizeof son);
    for(R int i=1,x,y;i<n;i++)
    {
        in(x),in(y);
        add(x,y),add(y,x);
    }
    dfs1(1,0);dfs2(1,1);
    for(R int x,y;m;m--)
    {
        scanf("%s",s);in(x),in(y);
        if(s[0]=='P')tchange(x,y,1);
        else printf("%lld\n",tquery(x,y));
    }
}