本文主要是介绍图论 Kruskal算法 并查集,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
#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1sum += 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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