[HDUOJ] 1233 还是畅通工程

//#pragma GCC optimize(2)
#include <cstdio>
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <string>
#include <cstring>
#include <algorithm>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <ctime>
#include <vector>
#include <fstream>
#include <list>
#include <iomanip>
#include <numeric>
using namespace std;
typedef long long ll;

const int MAXN = 1e6 + 10;

int father[MAXN];

struct node
{
	int from, to, val;

}edge[MAXN];

bool cmp(node a, node b)
{
	return a.val < b.val;
}

int findfather(int x)
{
	if(father[x] == x)
		return x;
	return father[x] = findfather(father[x]);
}

bool checkin(int x, int y)
{
	int p = findfather(x), q = findfather(y);
	if(p != q)
		return true;
	return false;
}

void join(int x, int y)
{
	int p = findfather(x), q = findfather(y);
	if(p != q)	
		father[p] = q;
}



int main()
{
    //ios::sync_with_stdio(false);

    //cin.tie(0);     cout.tie(0);

    int N, x, y, z;

    while(cin>>N && N)
    {
    	for(int i = 0; i < N + 100; i++)
			father[i] = i;
    	
    	N = N * (N - 1) / 2;
    	
		for(int i = 0; i < N; i++)
    	{
    		scanf("%d%d%d", &edge[i].from, &edge[i].to, &edge[i].val);
    	}
    	
    	sort(edge, edge + N, cmp);
    	
    	int sumedge = 0, sumlen = 0;

    	for(int i = 0; i < N; i++)
    	{
    		if(checkin(edge[i].from, edge[i].to))
    		{
    			join(edge[i].from, edge[i].to);
    			sumedge++;
    			sumlen += edge[i].val;
    		}

    		if(sumedge == N - 1)
    			break;
    	}
    	cout<<sumlen<<endl;
    }

    return 0;
}

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转载自blog.csdn.net/Zeolim/article/details/82531027
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