haogui

与树相关的数据题，在此看一到ali的笔试题

附上自己编写的代码

/**
 * @author whg
 * @date 2021/7/24 7:49 下午
 **/
public class Tree {

    private List<Node> Node = new ArrayList();

    public List<com.ali.node.Node> getNode() {
        return Node;
    }

    public void setNode(List<com.ali.node.Node> node) {
        Node = node;
    }
}


/**
 * @author whg
 * @date 2021/7/24 7:48 下午
 **/
public class Node {

    private String value;

    private List<Node> nodes = new ArrayList<>();

    public Node(String value) {
        this.value = value;
    }

    public Node(){

    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public List<Node> getNodes() {
        return nodes;
    }

    public void setNodes(List<Node> nodes) {
        this.nodes = nodes;
    }
}

/**
 * 将
 * @author whg
 * @date 2021/7/24 7:56 下午
 **/
public class Data2Tree2Json {

    private static Tree tree = new Tree();

    public static void toTree(String[] words){
        if(words == null){
            return;
        }

        //指向当前层级
        List<Node> nodes = tree.getNode();

        for (int i = 0; i < words.length; i++) {
            Node node = haveSimpleValue(nodes, words[i]);
            //没有则加入
            if(node == null){
                //记录新节点好向下继续遍历
                node = add2Nodes(nodes,words[i]);
            }

            // nodes 转移到下一层
            nodes = node.getNodes();
        }

    }

    /**
     * 判断是否存在一点的节点
     * @param nodes
     * @param word
     * @return
     */
    public static Node haveSimpleValue(List<Node> nodes, String word){
        List<Node> collect = nodes.stream()
                .filter(node -> node.getValue().equals(word))
                .collect(Collectors.toList());
        return  collect.isEmpty() ? null : collect.get(0);
    }

    /**
     * 将word加入nodes中
     * @param nodes
     * @param word
     */
    public static Node add2Nodes(List<Node> nodes, String word){
        if(nodes == null || word == null){
            return null;
        }
        Node node = new Node(word);
        nodes.add(node);
        return node;
    }

    public static String tree2Json(){
        List<Node> node = tree.getNode();
        return "{" + nodes2Json(node) + "}";
    }

    /**
     * 把nodes变成json
     * @param nodes
     * @return
     */
    public static String nodes2Json(List<Node> nodes){
        List<String> values = new ArrayList<>();
        for (int i = 0; i < nodes.size(); i++) {
            Node node = nodes.get(i);
            //下一层没有元素则拼接后返回
            if(node.getNodes().size() == 0){
                String value = "\"" + node.getValue() + "\"" + ":{}";
                values.add(value);
            }else {
                values.add("\"" + node.getValue() + "\"" + ":{" + nodes2Json(node.getNodes()) + "}");
            }
        }

        StringBuilder sb = new StringBuilder();
        values.forEach(json ->{
            sb.append(json).append(",");
        });
        return sb.substring(0,sb.length()-1).toString() ;
    }

    public static void main(String[] args) {
        String[] word = new String[]{"中国","浙江","杭州"};
        String[] word2 = new String[]{"中国","浙江","杭州","余杭区"};
        String[] word4 = new String[]{"中国","浙江","宁波"};
        String[] word3 = new String[]{"中国","广东"};
        String[] word5 = new String[]{"美国","纽约"};
        toTree(word);
        toTree(word2);
        toTree(word3);
        toTree(word4);
        toTree(word5);
        System.out.println(tree2Json());
    }

}