真正的Kruskal poj 1258（应用了并查集）

package com.liang.poj;

import java.util.Scanner;

public class Test1258Kruskal {
	static int n = 0;
	static int[][] cin = null;
	static int[][] result = null;
	static int index = 0;
	static int[] father = null;
	static int[] rank = null;

	public static void main(String[] args) throws Exception {
		Scanner scan = new Scanner(System.in);
		n = scan.nextInt();
		cin = new int[n][n];
		father = new int[n];
		result = new int[n * n - n][3];
		rank = new int[n];

		for (int i = 0; i < cin.length; i++) {
			for (int j = 0; j < cin[i].length; j++) {
				cin[i][j] = scan.nextInt();
			}
		}

		for (int i = 0; i < cin.length; i++) {
			for (int j = 0; j < cin[i].length; j++) {
				if (cin[i][j] != 0) {
					result[index][0] = i;
					result[index][1] = j;
					result[index][2] = cin[i][j];
					index++;
				}
			}
		}

		peixu();

		kruskal(0);

	}

	public static void kruskal(int count) {
		int sum = 0;
		makeSet();
		for (int i = 0; i < result.length; i++) {
			int a = result[i][0];
			int b = result[i][1];
			if (merge(a, b)) {
				sum += result[i][2];
				count++;
			}
			if(count == n-1) {
				break;
			}
		}

		System.out.println(sum);
	}

	public static void makeSet() {
		for (int i = 0; i < father.length; i++) {
			father[i] = i;
			rank[i] = 0;
		}
	}

	public static int findFather(int x) {
		if (x != father[x]) {
			x = findFather(father[x]);
		}
		return x;
	}

	public static boolean merge(int a, int b) {
		int fa = findFather(a);
		int fb = findFather(b);

		if (fa == fb) {
			return false;
		} else {
			if (rank[fa] >= rank[fb]) {
				father[fb] = fa;
				rank[fa]++;
			} else {
				father[fa] = fb;
				rank[fb]++;
			}
			return true;
		}

	}

	public static void peixu() { // 对权值进行排序
		for (int i = 0; i < result.length; i++) {
			if (result[i][2] == 0) {
				continue;
			}
			for (int j = i + 1; j < result.length; j++) {
				if (result[j][2] == 0) {
					continue;
				}
				if (result[i][2] > result[j][2]) {
					jiaohuan(i, j, 0);
					jiaohuan(i, j, 1);
					jiaohuan(i, j, 2);
				}
			}
		}
	}

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

}