图论 Kruskal算法 并查集

#include<iostream>
#include<cstring>
#include<string>
#include<cstdio>
#include<algorithm>
using namespace std;
#define MAX 80000
int father[MAX], son[MAX];
int v,v2, l;

struct Kruskal //存储边的信息
{
	int a;
	int b;
	int value;
};

bool cmp(const Kruskal & a, const Kruskal & b)
{
	return a.value < b.value;
}

int unionsearch(int x) //查找根结点+路径压缩
{
	return x == father[x] ? x : unionsearch(father[x]);
}

bool join(int x, int y) //合并
{
	int root1, root2;
	root1 = unionsearch(x);
	root2 = unionsearch(y);
	if(root1 == root2) //为环
		return false;
	else if(son[root1] >= son[root2])
		{
			father[root2] = root1;
			son[root1] += son[root2];
		}
		else
		{
			father[root1] = root2;
			son[root2] += son[root1];
		}
	return true;
}
//int mhash[MAX];
int main()
{
	int  ltotal, sum;
	int i,flag;
	Kruskal edge[MAX];

		scanf("%d%d%d", &v,&v2, &l);
		ltotal = 0, sum = 0, flag = 0;
		for(i = 0; i < v+v2; ++i) //初始化
		{
			father[i] = i;
			son[i] = 1;
//			mhash[i]=0;
		}
		int tem,temva;
		for(i = 1; i <= l ; ++i)
		{
			scanf("%d%d%d", &edge[i].a, &tem, &temva);
			edge[i].b=tem+v;
			edge[i].value=-temva;
		}
		sort(edge + 1, edge + 1 + l, cmp); //按权值由小到大排序
		for(i = 1; i <= l; ++i)
		{
			if(join(edge[i].a, edge[i].b))
			{
//				mhash[edge[i].a]=1;
//				mhash[edge[i].b]=1;
				ltotal++; //边数加1
				sum += edge[i].value; //记录权值之和
//				cout<<edge[i].a<<"->"<<edge[i].b<<endl;
			}
//			if(ltotal == v+v2 - 1) //最小生成树条件：边数=顶点数-1
//			{
//				flag = 1;
//				break;
//			}
		}
//		int s=0;
//		for(i=0;i<v+v2;i++){
//			if(mhash[i])s++;
//		}
		printf("%d\n",(v+v2)*10000+sum);
//		if(flag) printf("%d\n", sum);
//		else printf("data error.\n");

	return 0;
}
/*
5 5 8
4 3 6831
1 3 4583
0 0 6592
0 1 3063
3 3 4975
1 3 2049
4 2 2104
2 2 781
 */

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