# 1088. Confusing Number II

<https://leetcode.com/problems/confusing-number-ii>

## Description

A **confusing number** is a number that when rotated `180` degrees becomes a different number with **each digit valid**.

We can rotate digits of a number by `180` degrees to form new digits.

* When `0`, `1`, `6`, `8`, and `9` are rotated `180` degrees, they become `0`, `1`, `9`, `8`, and `6` respectively.
* When `2`, `3`, `4`, `5`, and `7` are rotated `180` degrees, they become **invalid**.

Note that after rotating a number, we can ignore leading zeros.

* For example, after rotating `8000`, we have `0008` which is considered as just `8`.

Given an integer `n`, return *the number of **confusing numbers** in the inclusive range* `[1, n]`.

**Example 1:**

```
**Input:** n = 20
**Output:** 6
**Explanation:** The confusing numbers are [6,9,10,16,18,19].
6 converts to 9.
9 converts to 6.
10 converts to 01 which is just 1.
16 converts to 91.
18 converts to 81.
19 converts to 61.
```

**Example 2:**

```
**Input:** n = 100
**Output:** 19
**Explanation:** The confusing numbers are [6,9,10,16,18,19,60,61,66,68,80,81,86,89,90,91,98,99,100].
```

**Constraints:**

* `1 <= n <= 109`

## ac

```java
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://jaywin.gitbook.io/leetcode/solutions/1088-confusing-number-ii.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.