感謝博主：https://www.luogu.com.cn/blog/116113X/solution-p2542

題意：略：

解法：

#include<bits/stdc++.h>
#define ll long long
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define per(i,n,a) for(int i=n;i>=a;i--)
#define endl '\n'
#define eps 0.000000001
#define pb push_back
#define mem(a,b) memset(a,b,sizeof(a))
#define
 
 IO ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
const int INF=0x3f3f3f3f;
const ll inf=0x3f3f3f3f3f3f3f3f;
const int mod=1e9+7;
const int maxn=1e5+5;
int tot,head[maxn];
struct E{
    int to,next;
}edge[maxn<<1];
void add(int u,int v){
    edge[tot].to=v;
    edge[tot].next=head[u];
    head[u]
 
=tot++;
}
struct nod{
    int t,a,b;
}dt[maxn];
int n,m,fa[maxn];
int find(int x){
    while(x!=fa[x]) x=fa[x]=fa[fa[x]];
    return x;
}
int uu[maxn],vv[maxn],vis[maxn];
map<pair<int,int>,int>mp;
int v[maxn],root;
int dep[maxn],siz[maxn],son[maxn];
void dfs1(int u,int f){
    fa[u]=f;
    dep[u]
 
=dep[f]+1;
    siz[u]=1;
    int maxsize=-1;
    for(int i=head[u];i!=-1;i=edge[i].next){
        int v=edge[i].to;
        if(v==f) continue;
        dfs1(v,u);
        siz[u]+=siz[v];
        if(siz[v]>maxsize){
            maxsize=siz[v];
            son[u]=v;
        }
    }
}
int tim,dfn[maxn],top[maxn],w[maxn];
void dfs2(int u,int t){
    dfn[u]=++tim;
    top[u]=t;
    if(!son[u]) return ;
    dfs2(son[u],t);
    for(int i=head[u];i!=-1;i=edge[i].next){
        int v=edge[i].to;
        if(v==fa[u]||v==son[u]) continue;
        dfs2(v,v);
    }
}
struct node{
    int l,r,sum,lz;
}tree[maxn<<2];
inline void build(int i,int l,int r){
    tree[i].l=l;tree[i].r=r,tree[i].lz=-1;
    if(l==r){
        tree[i].sum=1;
        return ;
    }
    ll mid=(l+r)>>1;
    build(2*i,l,mid);
    build(2*i+1,mid+1,r);
    tree[i].sum=tree[2*i].sum+tree[i*2+1].sum;
}
inline void push_down(int i){
    if(tree[i].lz!=-1){
        tree[i*2].lz=tree[i].lz;
        tree[i*2+1].lz=tree[i].lz;
        ll mid=(tree[i].l+tree[i].r)/2;
        tree[i*2].sum=tree[i].lz*(mid-tree[i*2].l+1);
        tree[i*2+1].sum=tree[i].lz*(tree[i*2+1].r-mid);
        tree[i].lz=-1;
    }
    return ;
}
inline void modify(int i,int l,int r,int k){
    if(tree[i].r<=r && tree[i].l>=l){
        tree[i].sum=k*(tree[i].r-tree[i].l+1);
        tree[i].lz=k;
        return ;
    }
    push_down(i);
    if(tree[i*2].r>=l)
        modify(i*2,l,r,k);
    if(tree[i*2+1].l<=r)
        modify(i*2+1,l,r,k);
    tree[i].sum=tree[i*2].sum+tree[i*2+1].sum;
}
inline int query(int i,int l,int r){
    if(tree[i].l>=l && tree[i].r<=r)  
        return tree[i].sum;
    if(tree[i].r<l || tree[i].l>r)  return 0;
    push_down(i);
    ll s=0;
    if(tree[i*2].r>=l)  s+=query(i*2,l,r);
    if(tree[i*2+1].l<=r)  s+=query(i*2+1,l,r);
    return s;
}
void mchain(int x,int y,int z){
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]])
            std::swap(x,y);
        modify(1,dfn[top[x]],dfn[x],z);
        x=fa[top[x]];
    }
    if(dep[x]>dep[y]) std::swap(x,y);
    modify(1,dfn[x]+1,dfn[y],z);
}
int qchain(int x,int y){
    int ret=0;
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]]) std::swap(x,y);
        ret+=query(1,dfn[top[x]],dfn[x]);
        x=fa[top[x]];
    }
    if(dep[x]>dep[y]) std::swap(x,y);
    ret+=query(1,dfn[x]+1,dfn[y]);
    return ret;
}
int main(){
    scanf("%d%d",&n,&m);mem(head,-1);
    rep(i,1,m){
        scanf("%d%d",&uu[i],&vv[i]);
    }
    int cnt=0;
    while(1){
        int op;scanf("%d",&op);
        if(op==-1) break;
        int a,b;scanf("%d%d",&a,&b);
        dt[++cnt]={op,a,b};
        if(!op) mp[{a,b}]=mp[{b,a}]=1;
    }
    rep(i,1,n) fa[i]=i;
    rep(i,1,m){
        int u=find(uu[i]),v=find(vv[i]);
        if(!mp[{uu[i],vv[i]}]&&fa[u]!=v){
            fa[u]=v;
            add(uu[i],vv[i]);
            add(vv[i],uu[i]);
            vis[i]=true;
        }
    }
    mem(fa,0);
    dfs1(1,-1);
    dfs2(1,1);
    build(1,1,n);
    rep(i,1,m){
        if(!vis[i]&&!mp[{uu[i],vv[i]}]){
            int a=uu[i],b=vv[i];
            mchain(a,b,0);
        }
    }
    stack<int> q;
    for(int i=cnt;i>=1;i--){
        int ans=0,t=dt[i].t,a=dt[i].a,b=dt[i].b;
        if(t){
            ans=qchain(a,b);
            q.push(ans);
        }else{
            mchain(a,b,0);
        }
    }
    while(!q.empty()){
        int now=q.top();
        cout<<now<<endl;
        q.pop();
    }
}