Equal With Deletions

2022-04-04.py

question = """

Given two strings n and m, return true if they are equal when both are entered into 
text editors. But: a # means a backspace character (deleting backwards), and a % means 
a delete character (deleting forwards).

Example:

> equalWithDeletions("a##x", "#a#x")
> true      // both strings become "x"

> equalWithDeletions("fi##f%%%th %%year #time###", "fifth year time")
> false     // the first string becomes "fart"


"""

import re

def equalWithDeletions(n, m):
    has_hash_p = re.compile(r'[^#]#')
    has_perc_p = re.compile(r'%[^%]')

    while has_hash_p.search(n):
        n = re.sub(r'[^#]#', '', n)
    while has_hash_p.search(m):
        m = re.sub(r'[^#]#', '', m)
    n = re.sub(r'^#+', '', n)
    m = re.sub(r'^#+', '', m)

    while has_perc_p.search(n):
        n = re.sub(r'%[^%]', '', n)
    while has_perc_p.search(m):
        m = re.sub(r'%[^%]', '', m)

    n = re.sub(r'%+$', '', n)
    m = re.sub(r'%+$', '', m)

    print(n == m)

equalWithDeletions("a##x", "#a#x")
equalWithDeletions("fi##f%%%th %%year #time###", "fifth year time")