Hdu 5274 Dylans loves tree (树链剖分模板)

Hdu 5274 Dylans loves tree (树链剖分模板)

题目传送门

#include <queue>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <vector>
#define ll long long
#define inf 1000000000LL
#define mod 1000000007
using namespace std;
int read()
{
    int x=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9')
    {
        if(ch=='-')f=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9')
    {
        x=x*10+ch-'0';
        ch=getchar();
    }
    return x*f;
}
const int N=1e5+10;
const int M=2e5+10;
int n,q,cnt,sz;
int v[N],dep[N],size[N],head[N],fa[N];
int pos[N],bl[N];
struct data{int to,next;}e[M];
struct seg{int l,r,sum;}t[N<<2];
void insert(int u,int v)
{
    e[++cnt].to=v;e[cnt].next=head[u];head[u]=cnt;
    e[++cnt].to=u;e[cnt].next=head[v];head[v]=cnt;
}
void init()
{
    sz=cnt=0;
    dep[1]=0;
    memset(head,0,sizeof(head));
    memset(size,0,sizeof(size));
    n=read();q=read();
    int x,y;
    for(int i=1;i<n;i++)
    {
		x=read();y=read();
		insert(x,y);
	}
    for(int i=1;i<=n;i++) v[i]=read();
}
void dfs1(int x)
{
    size[x]=1;
    for(int i=head[x];i;i=e[i].next)
    {
        if(e[i].to==fa[x])continue;
        dep[e[i].to]=dep[x]+1;
        fa[e[i].to]=x;
        dfs1(e[i].to);
        size[x]+=size[e[i].to];
    }
}
void dfs2(int x,int chain)
{
    int k=0;sz++;
    pos[x]=sz;//分配x结点在线段树中的编号
	bl[x]=chain;
    for(int i=head[x];i;i=e[i].next)
        if(dep[e[i].to]>dep[x]&&size[e[i].to]>size[k])
            k=e[i].to;//选择子树最大的儿子继承重链
    if(k==0)return;
    dfs2(k,chain);
    for(int i=head[x];i;i=e[i].next)
        if(dep[e[i].to]>dep[x]&&k!=e[i].to)
            dfs2(e[i].to,e[i].to);//其余儿子新开重链
}
void build(int k,int l,int r)//建线段树
{
    t[k].l=l;t[k].r=r;
    t[k].sum=0;
    if(l==r)return;
    int mid=(l+r)>>1;
    build(k<<1,l,mid);
    build(k<<1|1,mid+1,r);
}
void change(int k,int x,int y)//线段树单点修改
{
    int l=t[k].l,r=t[k].r,mid=(l+r)>>1;
    if(l==r){t[k].sum=y;return;}
    if(x<=mid)change(k<<1,x,y);
    else change(k<<1|1,x,y);
    t[k].sum=t[k<<1].sum^t[k<<1|1].sum;
}
int querysum(int k,int x,int y)//线段树区间求异或
{
    int l=t[k].l,r=t[k].r,mid=(l+r)>>1;
    if(l==x&&y==r)return t[k].sum;
    if(y<=mid)return querysum(k<<1,x,y);
    else if(x>mid)return querysum(k<<1|1,x,y);
    else {return querysum(k<<1,x,mid)^querysum(k<<1|1,mid+1,y);}
}
int solvesum(int x,int y)
{
	int sum=0;
    while(bl[x]!=bl[y])            //bl[x] 点x的链哈希值
    {
		if(dep[bl[x]]<dep[bl[y]])swap(x,y);
		sum^=querysum(1,pos[bl[x]],pos[x]);
		x=fa[bl[x]];
	}
	if(pos[x]>pos[y])swap(x,y);
	sum^=querysum(1,pos[x],pos[y]);
    return sum;
}
void solve()
{
    build(1,1,sz);
    for(int i=1;i<=n;i++)
        change(1,pos[i],v[i]+1);       //pos[i]: i节点的哈希值
	int op,ans,x,y;;
    for(int i=1;i<=q;i++)
    {
        op=read();x=read();y=read();
        if(op==0){v[x]=y;change(1,pos[x],y+1);}
        else
        {
            ans=solvesum(x,y);
            printf("%d
",ans-1);
        }
    }
}
int main()
{
    int T;
    T=read();
    while(T--){
       init();
       dfs1(1);
       dfs2(1,1);
	   solve();
	}
    return 0;
}