Java实现深度优先遍历和广度优先遍历

深度优先遍历

public static void depthterator(BiTree root){
        if(root == null){
            return;
        }
        Stack<BiTree> stack = new Stack<>(); //深度遍历，利用栈后进先出的特性
        stack.push(root);
        while(!stack.isEmpty()){
            BiTree current = stack.pop();
            System.out.println("--->" + current.val);
            if(current.right != null){
                stack.push(current.right); //右子树入栈
            }
            if(current.left != null){
                stack.push(current.left); //左子树入栈
            }
        }
    }

广度优先遍历（层次遍历）

public static void levelIterator(BiTree root){
        if(root == null){
            return;
        }
        LinkedList<BiTree> queue = new LinkedList<>(); //广度遍历，利用队列先进先出的特性
        queue.offer(root);
        while(!queue.isEmpty()){
            BiTree current = queue.poll();
            System.out.println("--->" + current.val);
            if(current.left != null){
                queue.offer(current.left); //左子树入队
            }
            if(current.right != null){
                queue.offer(current.right); //右子树入队
            }
        }
    }