poj 1751 Highways (最小生成树，空间卡常数有毒啊)

poj1751题目链接

题意：一开始有一些边，然后添加一些边，使得代价之和最小。

思路：先把给定的边merge掉。。然后计算其余可以添加的边。。。接下来就是最小生成树。。。

然而因为多开了一个750*750的数组空间被卡了常。。。毫无人性。。。。

/* ***********************************************
Author :111qqz
Created Time :2016年07月13日 星期三 19时53分29秒
File Name :code/poj/1751.cpp
 ************************************************ */

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
#include <ctime>
#define fst first
#define sec second
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define ms(a,x) memset(a,x,sizeof(a))
typedef long long LL;
#define pi pair < int ,int >
#define MP make_pair

using namespace std;
const double eps = 1E-8;
const int dx4[4]={1,0,0,-1};
const int dy4[4]={0,-1,1,0};
const int inf = 0x3f3f3f3f;
const int N=755;
int n;
int m;
int om;
pi ans[N*N];
bool conc[N*N];
int f[N];
struct Edge
{
    int u,v;
    double w;

    bool operator < (Edge b)const
    {
	return w<b.w;
    }
}edge[N*N];



struct point
{
    double  x,y;

    void input()
    {
	scanf("%lf%lf",&x,&y);
    }

    double dis( point b)
    {
	double res ;
	res = (x-b.x)*(x-b.x)+(y-b.y)*(y-b.y);
	return sqrt(res);
    }
}p[N];

void init()
{
    for ( int i = 1 ; i <= n ; i++) f[i] = i;
}

int root ( int x)
{
    if (x!=f[x] ) f[x] = root (f[x]);
    return f[x];
}

void merge( int x,int y)
{
    int rx = root (x);
    int ry = root (y);
    if (rx==ry) return ;
    f[rx] = ry;
}
int main()
{
#ifndef  ONLINE_JUDGE 
    freopen("code/in.txt","r",stdin);
#endif

    cin>>n;
    init();
    for ( int i = 1 ; i <= n ; i++) p[i].input();
    cin>>m;
    om = m;
    int cnt = 0 ;
    for ( int i = 1 ; i <= m ; i++)
    {
	int u,v;
	scanf("%d%d",&u,&v);
	if (root(u)==root(v)) continue;
	merge(u,v);
	cnt++;
    }

    m = 0 ;
    for ( int i = 1 ; i <= n ; i++)
	for ( int j = 1 ; j <= n ; j++)
	    if (i<j)
	    {
		m++;
		edge[m].u =i;
		edge[m].v = j ;
		edge[m].w = p[i].dis(p[j]);
	    }

    sort(edge+1,edge+m+1);
    double mst = 0 ;
    int num = 0 ;
    for ( int i = 1; i <= m ; i++)
    {
	int u = edge[i].u;
	int v = edge[i].v;
	double w = edge[i].w;
	if (cnt>=n-1) break;
	if (root(u)==root(v)) continue;
	//	    cout<<"u:"<<u<<" v:"<<v<<" w:"<<w<<endl;
	merge(u,v);
	cnt++;
	num++;
	mst+=w;
	ans[num]=make_pair(u,v);
    }
    //	cout<<"cnt:"<<cnt<<endl;
    sort(ans+1,ans+num+1);

    for ( int i = 1 ;i <= num ; i++)
	cout<<ans[i].fst<<" "<<ans[i].sec<<endl;



#ifndef ONLINE_JUDGE  
    fclose(stdin);
#endif
    return 0;
}