dijkstra算法java

Dijkstra算法是一种用于解决带权有向图最短路径问题的贪心算法。下面是Java实现Dijkstra算法的示例代码：

import java.util.*;

public class DijkstraAlgorithm {
    private static final int MAX = Integer.MAX_VALUE;
    
    public static void main(String[] args) {
        int[][] graph = {
            {0, 7, 9, MAX, MAX, 14},
            {7, 0, 10, 15, MAX, MAX},
            {9, 10, 0, 11, MAX, 2},
            {MAX, 15, 11, 0, 6, MAX},
            {MAX, MAX, MAX, 6, 0, 9},
            {14, MAX, 2, MAX, 9, 0}
        };
        dijkstra(graph, 0);
    }
    
    public static void dijkstra(int[][] graph, int start) {
        int n = graph.length;
        int[] dist = new int[n];
        boolean[] visited = new boolean[n];
        Arrays.fill(dist, MAX);
        dist[start] = 0;
        
        for (int i = 0; i < n - 1; i++) {
            int u = minDistance(dist, visited);
            visited[u] = true;
            
            for (int v = 0; v < n; v++) {
                if (!visited[v] && graph[u][v] != MAX && dist[u] != MAX
                        && dist[u] + graph[u][v] < dist[v]) {
                    dist[v] = dist[u] + graph[u][v];
                }
            }
        }
        printSolution(dist);
    }
    
    public static int minDistance(int[] dist, boolean[] visited) {
        int min = MAX, minIndex = -1;
        for (int i = 0; i < dist.length; i++) {
            if (!visited[i] && dist[i] <= min) {
                min = dist[i];
                minIndex = i;
            }
        }
        return minIndex;
    }
    
    public static void printSolution(int[] dist) {
        System.out.println("Vertex \t Distance from Source");
        for (int i = 0; i < dist.length; i++) {
            System.out.println(i + " \t " + dist[i]);
        }
    }
}

在这个示例中，我们定义了一个6 x 6的带权有向图，并使用Dijkstra算法计算从顶点0到其他顶点的最短路径。算法会输出每个顶点的最短距离。