java数据结构----图

图的存储结构:

代码实现

public class Graph {
    // 标记顶点数目
    private int V;
    // 标记边数目
    private int E;
    // 邻接表
    private Queue<Integer>[] adj;

    public Graph(int v) {
        V = v;
        this.E = 0;
        this.adj = new Queue[v];
        for (int i = 0; i < adj.length; i++) {
            adj[i] = new Queue<Integer>();
        }
    }
    public int getV(){
        return V;
    }
    public int getE(){
        return E;
    }
    // 将v和w顶点相连
    public void addEdge(int v, int w){
        // 无向图中
        adj[v].enqueue(w);
        adj[w].enqueue(v);
        E++;
    }
    // 获取v点相连的点
    public Queue<Integer> adj(int v){
        return adj[v];
    }
}

图的搜索

深度优先搜索

广度优先搜索

路径查找

有向图

拓扑排序

检测有向图中的环

顶点排序

加权无向图

public class EdgeWeightedGraph {
    private final int V;
    private int E;
    private Queue<Edge>[] adj;

    public EdgeWeightedGraph(int v) {
        V = v;
        E = 0;
        adj = new Queue[v];
        for (int i = 0; i < adj.length; i++) {
            adj[i] = new Queue<>();
        }
    }
    public int getV(){
        return V;
    }
    public int getE(){
        return E;
    }
    public void addEdge(Edge edge){
        int v = edge.either();
        int w = edge.other(v);
        adj[v].enqueue(edge);
        adj[w].enqueue(edge);
        E++;
    }
    public Queue<Edge> adj(int v){
        return adj[v];
    }
    public Queue<Edge> edges() throws InterruptedException {
        Queue<Edge> res = new Queue<>();
        for (int i = 0; i < adj.length; i++) {
            while (!adj[i].isEmpty()){
                Edge edge = adj[i].dequeue();
                int other = edge.other(i);
                if (other > i){
                    res.enqueue(edge);
                }
            }
        }
        return res;
    }
    class Edge implements Comparable<Edge>{
        private int v;
        private int w;
        private double weight;

        public Edge(int v, int w, double weight) {
            this.v = v;
            this.w = w;
            this.weight = weight;
        }
        public double getWeight(){
            return weight;
        }
        public int either(){
            return v;
        }
        public int other(int a){
            return a == v ? w : v;
        }

        @Override
        public int compareTo(Edge o) {
            double cmp =  this.weight - o.weight;
            if (cmp > 0){
                return 1;
            }else if (cmp< 0){
                return -1;
            }else {
                return 0;
            }
        }
    }
}