BZOJ - 1015 逆向并查集

Posted 2020-09-09 NWU_ACM

 1 #include <iostream>
 2 #include <algorithm>
 3 #include <cstring>
 4 #include <cstdio>
 5 #include <bitset>
 6 #include <vector>
 7 #include <queue>
 8 #include <stack>
 9 #include <cmath>
10 #include <list>
11 #include <set>
12 #include <map>
13 #define rep(i,a,b) for(int i = a;i <= b;++ i)
14 #define per(i,a,b) for(int i = a;i >= b;-- i)
15 #define mem(a,b) memset((a),(b),sizeof((a)))
16 #define FIN freopen("in.txt","r",stdin)
17 #define FOUT freopen("out.txt","w",stdout)
18 #define IO ios_base::sync_with_stdio(0),cin.tie(0)
19 #define mid ((l+r)>>1)
20 #define ls (id<<1)
21 #define rs ((id<<1)|1)
22 #define N 400010
23 #define INF 0x3f3f3f3f
24 #define INFF ((1LL<<62)-1)
25 using namespace std;
26 typedef long long LL;
27 typedef pair<int, int> PIR;
28 const double eps = 1e-8;
29  
30 int n, m, u, v, t, k[N], f[N], ans[N];
31 vector <int> G[N];
32 bool vis[N];
33 int getfa(int x){
34     return f[x] == x ? x : f[x] = getfa(f[x]);
35 }
36 int main()
37 {
38     //FIN;
39     scanf("%d %d", &n, &m);
40     rep(i, 1, m){ 
41         scanf("%d %d", &u, &v);
42         G[u].push_back(v);
43         G[v].push_back(u);
44     }
45     scanf("%d", &t);
46     rep(i, 1, t)    { scanf("%d", &k[i]); vis[k[i]] = true; }
47     rep(i, 0, n)    f[i] = i;
48  
49     int res = n-t;
50     rep(i, 0, n-1){
51         if(vis[i])  continue;
52         int x = getfa(i);
53         rep(j, 0, (int)G[i].size()-1){
54             if(vis[G[i][j]])    continue;
55             int y = getfa(G[i][j]);
56             if(x != y)  { f[y] = x; res--; }
57         }
58     }
59     /*int res = 0;
60     rep(i, 0, n-1)  { if(!vis[i] && getfa(i) == i)  res++; }*/
61     per(i, t, 0){
62         ans[i] = res++;
63         vis[k[i]] = false;
64         int x = getfa(k[i]);
65         rep(j, 0, (int)G[k[i]].size()-1){
66             if(vis[G[k[i]][j]]) continue;
67             int y = getfa(G[k[i]][j]);
68             if(x != y){ 
69                 f[y] = x;
70                 res--;
71             }
72         }
73     }
74     rep(i, 0, t)    printf("%d\n", ans[i]);
75     return 0;
76 }

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