Interview solutions (naive, no StackOverflow)

interview_solutions.py

#######
# One #
#######

import re


def longest_prefix(str_list):
    sorted_strs = sorted(str_list, key=lambda x: len(x))
    longest = sorted_strs[-1]
    return [
        longest[:i]
        for i, c in enumerate(longest)
        for other in sorted_strs[:-1]
        if not re.match(longest[: i + 1], other)
    ][0]


test_lists = [
    ["abcdefabc", "abcdfff", "abcodo"],
    ["aab", "adc", "aef"],
    ["abc", "def", "cbd"],
]

for l in test_lists:
    print(longest_prefix(l))

#######
# Two #
#######

from string import ascii_letters
import re


def reverse_letters(test_str):
    chars = [s for s in test_str if s in ascii_letters]
    backward = iter(reversed(chars))
    return re.sub(r"[a-zA-Z]", lambda x: next(backward), test_str, len(chars))


test_strings = [r"a#f*bc'", r"kcj&$ba#", r"&#*#", r"abcd%ef"]

for test in test_strings:
    print(reverse_letters(test))

#########
# Three #
#########


def hits_zero(group):
    nums, start = group
    if start < 0 or start > len(nums) or nums[start] == "X":
        return False
    if nums[start] == 0:
        return True
    left, right = start - nums[start], start + nums[start]
    nums[start] = "X"
    return hits_zero((nums, left)) or hits_zero((nums, right))


test_groups = [
    ([3, 1, 0, 2, 4], 3),
    ([3, 1, 0, 2, 4], 0),
    ([1, 4, 0, 1, 3, 2], 4),
    ([1, 4, 0, 1, 3, 2], 0),
]

for group in test_groups:
    print(hits_zero(group))