0分悬关求调

#include<bits/stdc++.h>
using namespace std;
int n,m,k,f[400005],n2;
vector<int>v[400005],vec;
int find(int x){
    return f[x]==x?x:f[x]=find(f[x]);
}
bool merge(int x,int y){
    int fx=find(x),fy=find(y);
    return fx==fy?false:(f[fx]=fy,n2--,true);
}
int main(){
    cin>>n>>m;n2=n;
    for(int i=1;i<=n;i++)f[i]=i;
    for(int i=1,x,y;i<=m;i++)
        {
            cin>>x>>y;
            v[x].push_back(y);v[y].push_back(x);
        }
    cin>>k;
    int a[k+5];bool b[n+5]={false};
    for(int i=1;i<=k;i++)cin>>a[i];
	for(int i=k;i>=1;i--)b[a[i]]=true;
	for(int i=1;i<=n;i++)if(b[i])for(int j=0;j<v[i].size();j++)merge(i,v[i][j]);
	cout<<n2<<endl;
	for(int i=1;i<=k;i++)
		{
			for(int j=0;j<v[a[i]].size();i++)merge(a[i],v[a[i]][j]);
			vec.push_back(n2);
		}
	for(int i=vec.size()-1;i>=0;i--)cout<<vec[i]<<endl;
	return 0;
}