### backspaceCompare 
from typing import *
def f_gold(s: str, t: str) -> bool:
    i, j, skip1, skip2 = len(s) - 1, len(t) - 1, 0, 0
    while i >= 0 or j >= 0:
        while i >= 0:
            if s[i] == '#':
                skip1 += 1
                i -= 1
            elif skip1:
                skip1 -= 1
                i -= 1
            else:
                break
        while j >= 0:
            if t[j] == '#':
                skip2 += 1
                j -= 1
            elif skip2:
                skip2 -= 1
                j -= 1
            else:
                break
        if i >= 0 and j >= 0:
            if s[i] != t[j]:
                return False
        elif i >= 0 or j >= 0:
            return False
        i, j = i - 1, j - 1
    return True