有权图单源最短路径Dijkstra算法

使用Dirkstra算法完成有权单源最短路径的算法，回忆一下当初学数据结构最难的图的部分，注意里面距离和收录点之间的运算关系，以及Dijkstra算法的步骤。示例为总共五个城市，五条路，城市编号从0到4，起始点为0，终点为3，路径为：0 - 4 => 5;0 - 1 => 2; 0 - 2 =>2; 1 - 3 =>1 ; 2 - 3 =>2;总共五条路径。

import java.util.*;public class Dijkstra {static int[] dist;//记录最短路径static int[][] map;//图的存储，邻接矩阵static boolean[] visited;        //收录使用static int M,N;//M个城市，N条路static int start,end;        //城市起点和终点static final int maxINF = 1 << 30;static int[] path;//记录经过的路径static void dijkstra(){dist[start] = 0;//起点距离为0visited[start] = true;        //收录起点Arrays.fill(path, -1);for( int i = 0 ; i < M ;i++)//初始化起点if( map[start][i] != maxINF ){dist[i] = map[start][i];path[i] = start;}while(true){int findMin = maxINF;int u = 0;for( int i = 0 ; i < M ; i++)//寻找当前未被收录且dist中最小的值if( !visited[i] && dist[i] < findMin){u = i;findMin = dist[i];}if( findMin == maxINF)//均被访问过break;visited[u] = true;//收录该顶点for( int i = 0 ; i < M ; i++){if( !visited[i] && dist[u] + map[u][i] < dist[i]){dist[i] = dist[u] + map[u][i];path[i] = u;}}}}static void printPath(){//利用堆栈实现输出路径 Deque<Integer> stack = new ArrayDeque<Integer>(); int e = end; while( path[e] != -1){ stack.push(e); e = path[e]; }System.out.print(start+" ");while( !stack.isEmpty()){int n = stack.pop();System.out.print(n+" ");}}public static void main(String[] args) {Scanner input = new Scanner(System.in);M = input.nextInt();//0 - M-1总共M个城市map = new int[M][M];dist = new int[M];visited = new boolean[M];path = new int[M];for( int i = 0 ; i < M ; i++)Arrays.fill(map[i], maxINF); //图的每一个节点初始化长度为无穷大Arrays.fill(dist, maxINF);//dist定义为正无穷大Arrays.fill(visited, false);N = input.nextInt();//N条路start = input.nextInt();//出发城市end = input.nextInt();//终点城市for( int i = 0 ; i < N ; i++){int x = input.nextInt();int y = input.nextInt();int d = input.nextInt();map[x][y] = d;}dijkstra();/*for( int i = 0 ; i < M ; i++){for( int j = 0 ; j < M ; j++)System.out.print(map[i][j]+" ");System.out.println();}for( int i = 0 ; i < M ; i++)System.out.print(dist[i]+" ");System.out.println();for( int i = 0 ; i < M ; i++)System.out.print(path[i]+" ");System.out.println();*/System.out.println(dist[end]);printPath();}}