P100

题目描述:https://leetcode-cn.com/problems/same-tree/

这个题目只要按照相同的顺序遍历一遍节点,判断节点是否相等即可,注意下对空节点的处理就好

  public boolean isSameTree(TreeNode p, TreeNode q) {
        Stack<TreeNode> stack = new Stack<>();
        stack.add(p);
        stack.add(q);
        while (!stack.isEmpty()) {
            TreeNode pNode = stack.pop();
            TreeNode qNode = stack.pop();
            if ((Objects.isNull(pNode) && Objects.nonNull(qNode))
                    ||(Objects.isNull(qNode) && Objects.nonNull(pNode))){
                return false;
            }else if (Objects.nonNull(pNode)&&Objects.nonNull(qNode)){
                if (!Objects.equals(pNode.val, qNode.val)) {
                    return false;
                }
                stack.add(pNode.left);
                stack.add(qNode.left);
                stack.add(pNode.right);
                stack.add(qNode.right);
            }
        }
        return true;
    }