# 0600. Non-negative Integers without Consecutive Ones

<https://leetcode.com/problems/non-negative-integers-without-consecutive-ones>

## Description

Given a positive integer `n`, return the number of the integers in the range `[0, n]` whose binary representations **do not** contain consecutive ones.

**Example 1:**

```
**Input:** n = 5
**Output:** 5
**Explanation:**
Here are the non-negative integers <= 5 with their corresponding binary representations:
0 : 0
1 : 1
2 : 10
3 : 11
4 : 100
5 : 101
Among them, only integer 3 disobeys the rule (two consecutive ones) and the other 5 satisfy the rule. 
```

**Example 2:**

```
**Input:** n = 1
**Output:** 2
```

**Example 3:**

```
**Input:** n = 2
**Output:** 3
```

**Constraints:**

* `1 <= n <= 109`

## ac

```java
```