Given a binary string `s` ​​​​​without leading zeros, return `true`​​​ if `s` contains at most one contiguous segment of ones. Otherwise, return `false`.

Example 1:

    Input: s = "1001"
    Output: false
    Explanation: The ones do not form a contiguous segment.

Example 2:

    Input: s = "110"
    Output: true

Constraints:

- `1 <= s.length <= 100`
- `s[i]`​​​​ is either `'0'` or `'1'`.
- `s[0]` is `'1'`.