Consecutive Ones

You are given a list of integers nums which contains at least one 1. Return whether all the 1s appear consecutively.

Constraints

• 1 ≤ n ≤ 100,000 where n is the length of nums

https://binarysearch.com/problems/Consecutive-Ones

Examples

Example 1

Input

• nums = [0, 1, 1, 1, 2, 3]

Output

• answer = True

Explanation

All the 1s appear consecutively here in the middle.

Example 2

Input

• nums = [1, 1, 0, 1, 1]

Output

• answer = False

Explanation

There’s two groups of consecutive 1s.

Solution