Check if Binary String Has at Most One Segment of Ones

Easy

Problem

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

A contiguous segment of ones means all the 1s in the string appear consecutively without any 0s between them.

Constraints

1 <= s.length <= 100
s[i] is either '0' or '1'
s[0] is '1' (no leading zeros)

Examples

Input: s = "1001"

Output: false

The ones do not form a contiguous segment. There is a '1' at index 0, then zeros, then another '1' at index 3.

Input: s = "110"

Output: true

The ones form a single contiguous segment at the beginning: '11'. The trailing '0' doesn't break continuity.

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