题解 | #二叉树遍历#

public class Main{
    static class Node{
        char val;
        Node left;
        Node right;
        public Node(){
            this.val = '\0';
            this.left = null;
            this.right = null;
        }
        public Node(char val){
            this.val = val;
            this.left = null;
            this.right = null;
        }
    }
    static int index = 0;
    // 根据前序遍历字符来构建一颗二叉树 
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
       while(scanner.hasNext()){
            String dest = scanner.nextLine();
            index = 0;
            Node root = createTree(dest);
            InfixOrder(root);
       }
    }

    static Node createTree(String dest){
        // 根 左子树 右子树 
        Node root = new Node(dest.charAt(index));
        index++;
        if(dest.charAt(index) != '#') root.left = createTree(dest);
        index++;
        if(dest.charAt(index) != '#') root.right = createTree(dest);
        return root;
    }

    static void InfixOrder(Node root){
        if(root == null) return;
        InfixOrder(root.left);
        System.out.print(root.val + " ");
        InfixOrder(root.right);
    }

}