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This commit is contained in:
Jacob Delgado 2023-08-31 22:51:11 -07:00
parent ba6c38c00e
commit c11cbf310c
1 changed files with 53 additions and 45 deletions
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98
NeetCodeRoadmap/Arrays_and_Hashing/125_Valid_Palindrome.py
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@ -1,57 +1,65 @@
import string import string
import math import math
def isPalindrome(s): # def isPalindrome(s):
""" # """
:type s: str # :type s: str
:rtype: bool # :rtype: bool
""" # """
# Create a translation table to remove uppercase letters and special characters # # Create a translation table to remove uppercase letters and special characters
# translation_table = str.maketrans("","", string.punctuation + string.whitespace) # # translation_table = str.maketrans("","", string.punctuation + string.whitespace)
translation_table = ''.join(c.lower() if c.isupper() or c.isalnum() else '' for c in s if c.isalnum() or c in string.whitespace) # translation_table = ''.join(c.lower() if c.isupper() or c.isalnum() else '' for c in s if c.isalnum() or c in string.whitespace)
# print(translation_table) # # print(translation_table)
if len(translation_table) == 2: # if len(translation_table) == 2:
if translation_table[0] == translation_table[1]: # if translation_table[0] == translation_table[1]:
return True # return True
else: # else:
return False # return False
# Use the translation table to remove uppercase letters and special characters # # Use the translation table to remove uppercase letters and special characters
# upper_string = s.translate(translation_table) # # upper_string = s.translate(translation_table)
# lower_string = upper_string.lower() # # lower_string = upper_string.lower()
lower_string = translation_table # lower_string = translation_table
half = len(lower_string)/2 # half = len(lower_string)/2
# Round the value down since middle value doesn't matter # # Round the value down since middle value doesn't matter
if len(lower_string)%2 != 0: # if len(lower_string)%2 != 0:
halfdown = int(math.floor(half)) # halfdown = int(math.floor(half))
else: # else:
halfdown = int(half) # halfdown = int(half)
# print(halfup) # # print(halfup)
# print(halfdown) # # print(halfdown)
first = [] # first = []
second = [] # second = []
print(lower_string) # print(lower_string)
for i in range(halfdown): # for i in range(halfdown):
# print(i) # # print(i)
# print(lower_string[i]) # # print(lower_string[i])
first.append(lower_string[i]) # first.append(lower_string[i])
if len(lower_string)%2 != 0: # if len(lower_string)%2 != 0:
for j in range(halfdown+1, len(lower_string)): # for j in range(halfdown+1, len(lower_string)):
second.insert(0, lower_string[j]) # second.insert(0, lower_string[j])
else: # else:
for j in range(halfdown, len(lower_string)): # for j in range(halfdown, len(lower_string)):
second.insert(0, lower_string[j]) # second.insert(0, lower_string[j])
print(first) # print(first)
print(second) # print(second)
if first == second: # if first == second:
return True # return True
else: # else:
return False # return False
#Fastest solution
# Operator ~ is the bitwise NOT operator (~x == -x-1 => ~0 == -1 => ~1 == -2 and etc),
# which expects just one argument. It performs logical negation on a given number by
# flipping all of its bits:
def isPalindrome(s: str) -> bool:
s = [c.lower() for c in s if c.isalnum()]
return all (s[i] == s[~i] for i in range(len(s)//2))
print(isPalindrome("A man, a plan, a canal: Panama")) print(isPalindrome("A man, a plan, a canal: Panama"))
print(isPalindrome("aa")) print(isPalindrome("aa"))