树剖和线段树没挂，应该是询问函数挂了，思路是找到含被修改过的节点的重链然后二分，求调

while(q--)
	{
		char opt;
		cin>>opt;
		if(opt=='C') 
		{	
			int x=read();
			change(dfn[x],dfn[x],1,1);
		}
		if(opt=='Q')
		{
			ans=0;
			int u=read();
			ask(dfn[u],dfn[u],1);
			if(ans)
			{
				printf("%d\n",u);
				continue;
			}
			while(top[u]!=1)
			{
				ask(dfn[top[u]],dfn[u],1);
				if(ans!=0) break;
				u=fa[top[u]];
			}
			ask(1,dfn[u],1);
			if(ans==0) 
			{
				puts("1");
				continue;
			}
		    int l=dfn[top[u]],r=dfn[u],mid;
			while(l<=r)
			{
				ans=0;
				mid=(l+r)>>1;
				ask(l,mid,1);
				if(ans!=0) r=mid-1;
				else l=mid+1;
			}
			printf("%d\n",l);
		}
	}