HDU 5438 Ponds dfs模拟

1 #include <iostream>
2 #include <cstdio>
3 #include <fstream>
4 #include <algorithm>
5 #include <cmath>
6 #include <deque>
7 #include <vector>
8 #include <queue>
9 #include <string>
10 #include <cstring>
11 #include <map>
12 #include <stack>
13 #include <set>
14 #define LL long long
15 #define eps 1e-8
16 #define INF 0x3f3f3f3f
17 #define MAXN 10005
18 using namespace std;
19 vector<int> G[MAXN];
20 int  father[MAXN], cnt[MAXN], du[MAXN];
21 LL v[MAXN];
22 bool rm[MAXN], vis[MAXN];
23 struct Node{
24     int pos, du;
25     Node(int pos = 0, int du = 0) :pos(pos), du(du){};
26 };
27 bool compare(Node x, Node y){
28     return x.du < y.du;
29 }
30 int find(int x){
31     if (father[x] == x) return x;
32     father[x] = find(father[x]);
33     return father[x];
34 }
35 void dfs(int x, int p){
36     vis[x] = true;
37     father[x] = p;
38     for (int i = 0; i < G[x].size(); i++){
39         int y = G[x][i];
40         if (rm[y] || vis[y]) continue;
41         dfs(y, p);
42     }
43 }
44 void dfs_rm(int x){
45     rm[x] = true;
46     for (int i = 0; i < G[x].size(); i++){
47         du[G[x][i]]--;
48         if (du[G[x][i]] < 2 && !rm[G[x][i]]) dfs_rm(G[x][i]);
49     }
50 }
51 Node node[MAXN];
52 int main()
53 {
54     //freopen("in.txt", "r", stdin);
55     int T;
56     int m, n;
57     scanf("%d", &T);
58     while (T--){
59         scanf("%d%d", &n, &m);
60         memset(du, 0, sizeof(du));
61         for (int i = 1; i <= n; i++){
62             scanf("%I64d", &v[i]);
63             G[i].clear();
64         }
65         int x, y;
66         for (int i = 1; i <= m; i++){
67             scanf("%d%d", &x, &y);
68             du[x]++;
69             du[y]++;
70             G[x].push_back(y);
71             G[y].push_back(x);
72         }
73         memset(rm, 0, sizeof(rm));
74         //sort(node + 1, node + n + 1, compare);
75         for (int i = 1; i <= n; i++){
76             //int x = node[i].pos;
77             if (du[i] > 1 || rm[i]) continue;
78             dfs_rm(i);
79         }
80         int p = 1;
81         memset(father, 0, sizeof(father));
82         memset(vis, 0, sizeof(vis));
83         for (int i = 1; i <= n; i++){
84             if (rm[i] || vis[i]) continue;
85             dfs(i, p);
86             p++;
87         }
88         memset(cnt, 0, sizeof(cnt));
89         for (int i = 1; i <= n; i++){
90             if (rm[i]) continue;
91             //int x = find(i);
92             cnt[father[i]]++;
93         }
94         LL ans = 0;
95         for (int i = 1; i <= n; i++){
96             if (cnt[father[i]] & 1){
97                 ans += v[i];
98             }
99         }
100         printf("%I64d\n", ans);
101     }
102 }