- Because we need O(1) space, we have to do in-place replace.
- In order not to store
countas a string, we need to replace elements with num backwards, then reverse what we’ve replace. That’s what the
reverse()helper is for.
Given an array of characters
chars, compress it using the following algorithm:
Begin with an empty string
s. For each group of consecutive repeating characters in
- If the group’s length is
1, append the character to
- Otherwise, append the character followed by the group’s length.
The compressed string
s should not be returned separately, but instead, be stored in the input character array chars. Note that group lengths that are 10 or longer will be split into multiple characters in
After you are done
modifying the input array, return the new length of the array.
You must write an algorithm that uses only constant extra space.
Input: chars = ["a","a","b","b","c","c","c"]