Five simple ways to tackle Palindrome Number (Easy) | LeetCode Practice #2

睡觉 — Fri, 10 Jul 2026 09:30:48 +0000

Palindrome Number

Given an integer x, return true if x is a palindrome, and false otherwise.

Python

####Two Pointer (Runtime: 19ms, Memory: 12.3MB)
    #DECLARE x: INTEGER
class Solution:
    def isPalindrome(self, x):
        y = str(x)
        Head = 0
        Tail = len(y) - 1
        while Head < Tail:
            if y[Head] != y[Tail]:
                return False
            Head += 1
            Tail -= 1
        return True



####Recursion (Runtime: 19ms, Memory: 12.3MB)
    #DECLARE x: INTEGER
class Solution:
    def isPalindrome(self, x):
        y = str(x)
        Length = len(y)
        if y[0] != y[-1]:
            return False
        if Length <= 2:
            return True
        return self.isPalindrome(y[1:-1])



####Slicing Radius-Check(Runtime: 0ms, Memory: 12.3MB)
    #DECLARE x: INTEGER
class Solution:
    def isPalindrome(self, x):
        y = str(x)
        Radius = len(y) // 2
        return y[:Radius] == y[::-1][:Radius]



####Mathematical Calculation (Runtime: 27ms, Memory: 12.3MB)
    #DECLARE x: INTEGER
class Solution:
    def isPalindrome(self, x):
        if x < 0:
            return False
        Rev = 0
        Temp = x
        while Temp > 0:
            Rev = Rev * 10 + (Temp%10)
            Temp = Temp // 10
        return x == Rev



####Mathematical Radius-Check (Runtime: 9ms, Memory: 12.4MB)
    #DECLARE x: INTEGER
class Solution:
    def isPalindrome(self, x):
        if x < 0 or ((x%10==0) and (x!=0)):
            return False
        Temp = x
        Rev = 0
        while Temp > Rev:
            Rev = Rev * 10 + (Temp%10)
            Temp = Temp // 10
        if Temp == Rev or Temp == (Rev//10):
            return True
        return False

Two Sum and the use of Dictionary (Easy) | LeetCode Practice #1

睡觉 — Fri, 10 Jul 2026 09:23:30 +0000

Two Sum

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

(You may assume that each input would have exactly one solution, and you may not use the same element twice. You can return the answer in any order.)

Python

####Double FOR Loops (Runtime: 2100ms, Memory: 13.3MB)
    #DECLARE nums: ARRAY of INTEGER
    #DECLARE target: INTEGER
class Solution:
    def twoSum(self, nums, target):
        Length = len(nums)
        for i in range(Length - 1):
            for j in range((i + 1), Length):
                if nums[i] + nums[j] == target:
                    return i, j
        return None



####Hashing Algorithm (Runtime: 0ms, Memory: 12.9MB)
    #DECLARE nums: ARRAY of INTEGER
    #DECLARE target: INTEGER
class Solution:
    def twoSum(self, nums, target):
        Seen = {}
        for i, Value in enumerate(nums):
            if (target - Value) in Seen:
                return Seen[target - Value], i
            Seen[Value] = i
        return None

DEV Community: 睡觉

Five simple ways to tackle Palindrome Number (Easy) | LeetCode Practice #2

Palindrome Number

Python

Two Sum and the use of Dictionary (Easy) | LeetCode Practice #1

Two Sum

Python