HDU 5438 Ponds dfs模拟

2015 ACM/ICPC Asia Regional Changchun Online

题意：n个池塘，删掉度数小于2的池塘，输出池塘数为奇数的连通块的池塘容量之和.

思路：两个dfs模拟就行了

 #include <iostream>
 #include <cstdio>
 #include <fstream>
 #include <algorithm>
 #include <cmath>
 #include <deque>
 #include <vector>
 #include <queue>
 #include <string>
 #include <cstring>
 #include <map>
 #include <stack>
 #include <set>
 #define LL long long
 #define eps 1e-8
 #define INF 0x3f3f3f3f
 #define MAXN 10005
 using namespace std;
 vector<int> G[MAXN];
 int  father[MAXN], cnt[MAXN], du[MAXN];
 LL v[MAXN];
 bool rm[MAXN], vis[MAXN];
 struct Node{
     int pos, du;
     Node(int pos = , int du = ) :pos(pos), du(du){};
 };
 bool compare(Node x, Node y){
     return x.du < y.du;
 }
 int find(int x){
     if (father[x] == x) return x;
     father[x] = find(father[x]);
     return father[x];
 }
 void dfs(int x, int p){
     vis[x] = true;
     father[x] = p;
     for (int i = ; i < G[x].size(); i++){
         int y = G[x][i];
         if (rm[y] || vis[y]) continue;
         dfs(y, p);
     }
 }
 void dfs_rm(int x){
     rm[x] = true;
     for (int i = ; i < G[x].size(); i++){
         du[G[x][i]]--;
         if (du[G[x][i]] <  && !rm[G[x][i]]) dfs_rm(G[x][i]);
     }
 }
 Node node[MAXN];
 int main()
 {
     //freopen("in.txt", "r", stdin);
     int T;
     int m, n;
     scanf("%d", &T);
     while (T--){
         scanf("%d%d", &n, &m);
         memset(du, , sizeof(du));
         for (int i = ; i <= n; i++){
             scanf("%I64d", &v[i]);
             G[i].clear();
         }
         int x, y;
         for (int i = ; i <= m; i++){
             scanf("%d%d", &x, &y);
             du[x]++;
             du[y]++;
             G[x].push_back(y);
             G[y].push_back(x);
         }
         memset(rm, , sizeof(rm));
         //sort(node + 1, node + n + 1, compare);
         for (int i = ; i <= n; i++){
             //int x = node[i].pos;
             if (du[i] >  || rm[i]) continue;
             dfs_rm(i);
         }
         int p = ;
         memset(father, , sizeof(father));
         memset(vis, , sizeof(vis));
         for (int i = ; i <= n; i++){
             if (rm[i] || vis[i]) continue;
             dfs(i, p);
             p++;
         }
         memset(cnt, , sizeof(cnt));
         for (int i = ; i <= n; i++){
             if (rm[i]) continue;
             //int x = find(i);
             cnt[father[i]]++;
         }
         LL ans = ;
         for (int i = ; i <= n; i++){
             if (cnt[father[i]] & ){
                 ans += v[i];
             }
         }
         printf("%I64d\n", ans);
     }
 }