n级阶梯，每次走一步或两步，问最多有多少种走法 二叉树实现(面试题)

NodeTree类

public class NodeTree {
    private int num;
    private NodeTree left;
    private NodeTree right;
    public int getNum() {
        return num;
    }
    public void setNum(int num) {
        this.num = num;
    }
    public NodeTree getLeft() {
        return left;
    }
    public void setLeft(NodeTree left) {
        this.left = left;
    }
    public NodeTree getRight() {
        return right;
    }
    public void setRight(NodeTree right) {
        this.right = right;
    }
    public NodeTree() {
        super();
    }
    public NodeTree(int num) {
        super();
        this.num = num;
    }
    public NodeTree(int num, NodeTree left, NodeTree right) {
        super();
        this.num = num;
        this.left = left;
        this.right = right;
    }
    
    

}

主要用迭代实现

public class Lianxi03 {

    private static int num=0;
    public static void main(String[] args) {
        NodeTree nodeTree=new NodeTree(0);
        
        
        method02(nodeTree,100);
        System.out.println(num);
    }
    
    

    public static void method02(NodeTree nodeTree,int num1){
        if(nodeTree.getNum()==num1){
            ++num;
        }else if (nodeTree.getNum()>num1) {
            
        }else if (nodeTree.getNum()<num1){
            int temp=nodeTree.getNum();
        //    System.out.println(temp+"******"+num);
            
            NodeTree tempnode =nodeTree;
            nodeTree.setLeft(new NodeTree());
            nodeTree=nodeTree.getLeft();
            nodeTree.setNum(temp+1);
            method02(nodeTree,num1);
            
            tempnode.setRight(new NodeTree());    
            nodeTree=tempnode.getRight();
            
            nodeTree.setNum(temp+2);
            method02(nodeTree,num1);
        }
    }
}