最小代价生成树

Posted 2020-09-19 slgkaifa

#include<iostream>
using namespace std;
const int Max = 100;
int p[Max][Max];
const int maxCost = 99;
int lowcost[Max];
int nearest[Max];
bool mark[Max];
void Prime(int k,int n)
{
	memset(lowcost, 99, sizeof(lowcost));
	memset(nearest, -1, sizeof(nearest));
	memset(mark, false, sizeof(mark));
	nearest[k] = k;
	lowcost[k] = 0;
	mark[k] = true;
	//k is the the point you have added the set
	for (int i = 0; i < n; i++)
	{
		//update lowcost and nearest
		for (int j = 0; j < n; j++)
		{
			if (p[k][j] != 0 && !mark[j] && lowcost[j] > p[k][j])
			{
				lowcost[j] = p[k][j];
				nearest[j] = k;
			}
		}
		//find the min lowcost
		int min = maxCost;
		for (int j = 0; j < n; j++)
		{
			if (!mark[j] && min > lowcost[j])
			{
				min = lowcost[j];
				k = j;
			}
		}
		mark[k] = true;
	}


}

int main()
{
	freopen("sample_input.txt","r",stdin);
	int vertex, edge;
	cin >> edge >> vertex;
	int u, v, cost;
	for (int i = 0; i < vertex; i++)
	{
		cin >> u >> v >> cost;
		p[u][v] = cost;
		p[v][u] = cost;
	}
	Prime(0, edge);
	return 0;
}