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));
	}
}