Kata

This is the simple version of Fastest Code series. If you need some challenges, please try the Performance version

Task:

This time, we coding halfIt with a string.

Give you a string s, return "Half" of s.

What does "Half" mean? In this kata, "Half" means:

If a char in s appear more than one time, remove half and left half.

Some example to help you understand the rules:

halfIt("aabb")="ab"
halfIt("abab")="ab"
s has two "a" and two "b", so first "a" and "b" left

halfIt("aaab")=???
halfIt("abaa")=???
When number of a char is odd, like "aaa"
We can't left one and half "a", we need "round" it to 2
And we always keep chars which at leftside of s
So first "a",second "a" and a "b" left, last "a" should removed
 "aaab"-->"aab", "abaa"-->"aba"

halfIt("!!??")="!?"
It should work properly in all types of chars, not only letters

halfIt("CcCccccccCcCCcC")="CcCccccC"
It should not ignore the case, C and c are different

If s is not a string, return ""
halfIt(1)=""
halfIt([])=""
halfIt(true)=""
halfIt({})=""
halfIt(null)=""
halfIt(undefined)=""

Series:

• Bug in Apple
• Father and Son
• Jumping Dutch act
• Planting Trees
• Give me the equation
• Find the murderer
• Reading a Book
• Eat watermelon
• Special factor
• Guess the Hat
• Symmetric Sort
• Are they symmetrical?
• Max Value
• Trypophobia
• Virus in Apple
• Balance Attraction
• Remove screws I
• Remove screws II
• Regular expression compression
• Collatz Array(Split or merge)
• Tidy up the room
• Waiting for a Bus