# Longest Sequence of Consecutive Zeroes
by Helen Yu
tags: strings, loops, language_fundamentals

## Summary
> Write a function that returns the longest sequence of consecutive zeroes in a binary string.
> Examples
> longestZero("01100001011000") ➞ "0000"
> longestZero("100100100") ➞ "00"
> longestZero("11111") ➞ ""
> Notes
> If no zeroes exist in the input, return an empty string.

## Instructions
Write a function that returns the longest sequence of consecutive zeroes in a binary string.

### Examples
```
longestZero("01100001011000") ➞ "0000"

longestZero("100100100") ➞ "00"

longestZero("11111") ➞ ""
```

### Notes
If no zeroes exist in the input, return an empty string.