Kruskal 最小生成树（输出最小生成树的路径，权值的和） 参考poj 1258

输入无向图的，矩阵存储格式，

package com.liang.poj;

import java.util.Scanner;

public class Test2485Kruskal {
	static int n = 0;
	static int[][] cin = null;
	static boolean[] visited = null;        //对顶点进行标记
	static int[][] brimCollection = null;   //边的集合
	static int index = 0;
	static int[] path = null;              //记录路径和路径边上的权值
	static int pathIndex = 0;

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		while (scan.hasNext()) {
			n = scan.nextInt();
			cin = new int[n][n];
			visited = new boolean[n];
			brimCollection = new int[n * n - n][3];
			path = new int[n - 1];

			for (int i = 0; i < cin.length; i++) { // 初始化cin brimCollection
				for (int j = 0; j < cin[i].length; j++) {
					cin[i][j] = scan.nextInt();
					if (cin[i][j] != 0) {
						brimCollection[index][0] = i;
						brimCollection[index][1] = j;
						brimCollection[index++][2] = cin[i][j];
					}
				}
			}

			sort();

			path[pathIndex++] = 0;
			visited[brimCollection[0][0]] = true;
			visited[brimCollection[0][1]] = true;

			kruskal();
			
			for(int i=0; i<path.length; i++) {                       //对路径和权值进行输出
				System.out.print(brimCollection[path[i]][0] + " ");
				System.out.print(brimCollection[path[i]][1] + " ");
				System.out.println();
			}
			
			int sum = 0;
			for(int i=0; i<path.length; i++) {                       
				sum += brimCollection[path[i]][2];
			}
			System.out.println(sum);       //输出最小生成树，权值的和
			
		}
	}

	public static void kruskal() {      //克鲁斯卡尔算法
		int count = 1;
		for (int i = 1; i < brimCollection.length; i++) {
			int a = brimCollection[i][0];
			int b = brimCollection[i][1];
			if ((!visited[a] && visited[b]) || (visited[a] && !visited[b])) {
				visited[a] = true;
				visited[b] = true;
				path[pathIndex++] = i;
				i = 0;
				count ++ ;
			}
			if(count == n) {
				break;
			}
		}
	}

	public static void sort() {            //对所有的边按权值进行排序
		for (int i = 0; i < brimCollection.length; i++) {
			if (brimCollection[i][2] == 0) {
				break;
			}
			for (int j = i + 1; j < brimCollection.length; j++) {
				if (brimCollection[j][2] == 0) {
					break;
				}
				if (brimCollection[i][2] > brimCollection[j][2]) {
					exchange(i, j, 0);
					exchange(i, j, 1);
					exchange(i, j, 2);
				}
			}
		}
	}

	public static void exchange(int i, int j, int cos) {
		int x = 0;
		x = brimCollection[i][cos];
		brimCollection[i][cos] = brimCollection[j][cos];
		brimCollection[j][cos] = x;
	}

}