並查集+連結串列

https://blog.csdn.net/Wen_Yongqi/article/details/107443575

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 const int maxn=8e5+10;
 4 struct node
 5 {
 6     int v,nxt;
 7 }G[maxn*2];
 8 int head[maxn]; int num; int last[maxn];
 9 int fa[maxn];
10 void add(int u,int v)
11 {
12     G[++num].v=v;G[num].nxt=head[u];head[u]=num;
 
13     if(!last[u]) last[u]=num;
14 }
15 int Found(int x){return x==fa[x]?x:fa[x]=Found(fa[x]);}
16 int main()
17 {
18     int T;
19     scanf("%d",&T);
20     while(T--){
21         num=0;
22         int n,m;
23         scanf("%d%d",&n,&m);
24         for(int i=0;i<=n;i++){
25             fa[i]=i;
 
26             head[i]=last[i]=0;
27         }
28         for(int i=1;i<=m;i++){
29             int u,v;
30             scanf("%d%d",&u,&v);
31             u++;v++;
32             add(u,v);add(v,u);
33         }
34         int op;
35         scanf("%d",&op);
36         while(op--)
37         {
 
38             int x;
39             scanf("%d",&x);
40             x++;
41             if(x!=Found(x))continue;
42             head[0]=last[0]=0;
43             for(int i=head[x];i;i=G[i].nxt)
44             {
45                 int v=G[i].v;
46                 int fv=Found(v);
47                 if(fv==x)continue;
48                 fa[fv]=x;
49                 G[last[fv]].nxt=head[0];
50                 head[0]=head[fv];
51                 if(!last[0])
52                     last[0]=last[fv];
53             }
54             head[x]=head[0];
55             last[x]=last[0];
56         }
57         for(int i=1;i<=n;i++)
58             printf("%d ",Found(i)-1);
59         printf("\n");
60     }
61 }