swust2619

发表于 | 分类于 ， ， | 阅读数 次

链接:swust2619

题解

  • 树链剖分,初始置为0,毁坏一个点置1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<algorithm>
#define rep(i,x,y) for(register int i=x;i<=y;++i)
#define repd(i,x,y) for(register int i=x;i>=y;--i)
#define ll long long
#define lowbit(x) x&(-x)
using namespace std;
const int N=2e5+50;
int n,m,id[N],rt[N<<2],top[N],hson[N],size[N],deep[N],head[N],f[N],x,y,op,cnt;
struct node{
    int v,nxt;
    inline void init(int a,int b){v=a;nxt=b;}
}e[N];
inline void adde(int u,int v){
    e[++cnt].init(v,head[u]);
    head[u]=cnt;
}
void dfs1(int x){
    size[x]=1;
    for(int i=head[x],v;i;i=e[i].nxt)if((v=e[i].v)!=f[x]){
        f[v]=x;
        deep[v]=deep[x]+1;
        dfs1(v);
        size[x]+=size[v];
        if(size[hson[x]]<size[v])hson[x]=v;
    }
}
void dfs2(int x,int t){
    top[x]=t;id[x]=++cnt;
    if(hson[x])dfs2(hson[x],t);
    for(int i=head[x],v;i;i=e[i].nxt)if(hson[x]!=(v=e[i].v)&&v!=f[x])dfs2(v,v);
}
inline void update(int x,int y){for(register int i=x;i<=n;i+=lowbit(i))rt[i]+=y;}
inline int query(int x){int ans=0;for(register int i=x;i;i-=lowbit(i))ans+=rt[i];return ans;}
inline int check(int x,int y){
    while(top[x]!=top[y]){
        if(deep[top[x]]<deep[top[y]])swap(x,y);
        if(query(id[x])-query(id[top[x]]-1))return 0;
        x=f[top[x]];
    }
    if(id[x]<id[y])swap(x,y);
    return query(id[x])-query(id[y]-1)==0;
}

int main(){
    scanf("%d%d",&n,&m);
    rep(i,2,n){
        scanf("%d%d",&x,&y);
        adde(x,y);adde(y,x);
    }
    dfs1(1);cnt=0;
    dfs2(1,1);
    while(m--){
        scanf("%d",&op);
        if(op==1){
            scanf("%d%d",&x,&y);
            puts(check(x,y)?"YES":"NO");
        }
        else if(op==2){scanf("%d",&x);update(id[x],-1);}
        else {scanf("%d",&x);update(id[x],1);}
    }
    return 0;
}