bzoj1015: [JSOI2008]星球大战starwar

题解:并查集;

发现按顺序拆集合不行,就干脆反过来来合并集合;

 1 #include<iostream>
 2 #include<cstring>
 3 #include<cstdio>
 4 #include<cstdlib>
 5 #include<algorithm>
 6 #include<iomanip>
 7 #include<map>
 8 #include<set>
 9 #include<vector>
10 #include<ctime>
11 #include<cmath>
12 using namespace std;
13 const int maxn=404000;
14 struct node{
15     int y,next;
16 }e[maxn];
17 int linkk[maxn],len=0,fa[maxn],vis[maxn],q[maxn],g[maxn];
18 int n,m,k;
19 void insert(int x,int y){
20     e[++len].y=y;
21     e[len].next=linkk[x];
22     linkk[x]=len;
23 }
24 int getfather(int x){
25     int y=x,temp;
26     while(fa[y]!=y)y=fa[y];
27     while(y!=x){
28         temp=fa[x];
29         fa[x]=y;
30         x=temp;
31     }
32     return y;
33 }
34 bool Union(int x,int y){
35     x=getfather(x);y=getfather(y);
36     if(x==y)return 0;
37     fa[x]=y;return 1;
38 }
39 void work(){
40     scanf("%d %d",&n,&m);int x,y;
41     for(int i=1;i<=m;i++){
42         scanf("%d %d",&x,&y);x++,y++;
43         insert(x,y);insert(y,x);
44     }
45     scanf("%d",&k);
46     for(int i=1;i<=k;i++){scanf("%d",&q[i]);q[i]++;vis[q[i]]=1;}
47     for(int x=1;x<=n;x++){
48         fa[x]=x;
49         if(vis[x])continue;
50         for(int i=linkk[x];i;i=e[i].next){
51             if(vis[e[i].y])continue;
52             Union(x,e[i].y);
53         }
54     }
55     int ans=0;
56     for(int i=1;i<=n;i++){
57         fa[i]=getfather(i);
58         if(fa[i]==i&&!vis[i])ans++;
59     }
60     for(int j=k;j>=1;j--){
61         x=q[j];vis[x]=0;
62         for(int i=linkk[x];i;i=e[i].next){
63             if(vis[e[i].y])continue;
64             if(Union(e[i].y,x))ans--;
65         }
66         g[j]=ans;
67     }
68     for(int i=1;i<=k;i++)printf("%d\n",g[i]);
69 }
70 int main(){
71     work();
72     return 0;
73 }
View Code

 

posted @ 2016-09-29 15:13  CHADLZX  阅读(...)  评论(...编辑  收藏