Gym - 100203H Highways 最小生成树

题意：平面上n个点修路，已经修好了m条，再修若干条使得点之间连通，求最小代价的方案。

思路:基本上是裸的最小生成树了，我这里存边直接存在multyset了，取的时候也比较方便，我本来就是这么考虑的，队友打了一发朴素的排序的超时了。

 #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 755
 using namespace std;
 struct Edge{
     int from, to;
     LL dis;
     Edge(int from, int to, LL dis):from(from), to(to), dis(dis){};
     bool operator <(const Edge &b) const{
         return dis < b.dis;
     }
 };
 multiset<Edge> s;
 struct Point{
      int x, y;
 }p[MAXN];
 LL dis[MAXN][MAXN];
 bool vis[MAXN][MAXN];
 int father[MAXN];
 int scan(){
     int res = , ch, flag = ;

     if((ch = getchar()) == '-')
         flag = ;

     else if(ch >= '' && ch <= '')
         res = ch - '';
     while((ch = getchar()) >= '' && ch <= '' )
         res = res *  + ch - '';

     return flag ? -res : res;
 }
 LL getdis(Point a, Point b){
     LL x = abs(a.x - b.x);
     LL y = abs(a.y - b.y);
     return x * x + y * y;
 }
 int find(int x){
     if(father[x] == x) return x;
     father[x] = find(father[x]);
     return father[x];
 }
 int main()
 {
 #ifndef ONLINE_JUDGE
     freopen("in.txt", "r", stdin);
     //freopen("out.txt", "w", stdout);
 #endif // OPEN_FILE
     int n = scan();
     for(int i = ; i <= n; i++){
         father[i] = i;
         p[i].x = scan();
         p[i].y = scan();
     }
     s.clear();
     LL dis;
     for(int i = ; i <= n; i++){
         for(int j = i + ; j <= n; j++){
             dis = getdis(p[i] ,p[j]);
             s.insert(Edge(i, j, dis));
         }
     }
     int m =scan();
     int x, y;
     for(int i = ; i <= m; i++){
         x = scan();
         y = scan();
         vis[x][y] = true;
         x = find(x);
         y = find(y);
         if(x == y) continue;
         father[x] = y;
     }
     multiset<Edge>::iterator it = s.begin();
     while(it != s.end()){
         Edge u = *it;
         it++;
         if(vis[u.from][u.to] || vis[u.to][u.from]) continue;
         x = find(u.from);
         y = find(u.to);
         if(x == y) continue;
         father[x] = y;
         printf("%d %d\n", u.from, u.to);
     }

 }