思路：

考虑时光倒流

这不就是并查集裸题了…………….

//By SiriusRen#include 
     
      #include 
      
       #include 
       
        using namespace std;#define N 500500int n,q,xx,yy,v[N],first[N],next[N],tot,fa[N],f[N],ask[N],vis[N],ans[N];char op[N][5];int find(int x){return x==f[x]?x:f[x]=find(f[x]);}void add(int x,int y){v[tot]=y,next[tot]=first[x],first[x]=tot++;}void dfs(int x){for(int i=first[x];~i;i=next[i])if(v[i]!=fa[x])fa[v[i]]=x,dfs(v[i]);}int main(){    freopen("tree.in","r",stdin);    freopen("tree.out","w",stdout);    memset(first,-1,sizeof(first));    scanf("%d%d",&n,&q);    for(int i=1;i