AlgoMonster: The Most Structured Way to Prepare for Coding Interviews

Valid Palindrome

Easy

Given a string s, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

Example:

Input: s = "A man, a plan, a canal: Panama"
Output: true
Explanation: After removing non-alphanumeric characters, it becomes "amanaplanacanalpanama", which is a palindrome.

Input: s = "race a car"
Output: false
Explanation: After removing non-alphanumeric characters, it becomes "raceacar", which is not a palindrome.

Test Cases

Input

Do geese see God

Expected Output

true

Step 1

Step 2

Step 3

Step 1: Identify the Pattern

Brute Force1

Two Pointers2

Dynamic Programming3

Hashing4

Valid Palindrome

Easy

Given a string s, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

Example:

Input: s = "A man, a plan, a canal: Panama"
Output: true
Explanation: After removing non-alphanumeric characters, it becomes "amanaplanacanalpanama", which is a palindrome.

Input: s = "race a car"
Output: false
Explanation: After removing non-alphanumeric characters, it becomes "raceacar", which is not a palindrome.

Test Cases

Input

Do geese see God

Expected Output

true

Step 1

Step 2

Step 3

Step 1: Identify the Pattern

Brute Force1

Two Pointers2

Dynamic Programming3

Hashing4

Example:

Test Cases

Example:

Test Cases

Study Notes

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