Valid Palindrome

**Problem Statement:** A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers. Given a string `s`, return `true` if it is a palindrome, or `false` otherwise. **Hint / Expected Approach:** Skip non-alphanumeric, case-insensitive compare **Edge Cases to Consider:** - (1) Empty string - (2) Single character - (3) String with only spaces/punctuation

Examples

Example 1

Input: "A man, a plan, a canal: Panama"

Output: True

Example 2

Input: "race a car"

Output: False

Example 3

Input: " "

Output: True

Constraints

▪1 <= data.length <= 10^5
▪Memory complexity must be O(1) or O(k)
▪Ensure non-overlapping pointer access

Watch Out For Edge Cases

▪Empty string
▪Single character
▪String with only spaces/punctuation

Frequently Asked At

AmazonMicrosoftMetaAppleTCS

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easy

Two Pointer

Valid Palindrome

Examples

Example 1

Input: "A man, a plan, a canal: Panama"

Output: True

Example 2

Input: "race a car"

Output: False

Example 3

Input: " "

Output: True

Constraints

▪1 <= data.length <= 10^5
▪Memory complexity must be O(1) or O(k)
▪Ensure non-overlapping pointer access

Watch Out For Edge Cases

▪Empty string
▪Single character
▪String with only spaces/punctuation

Frequently Asked At

AmazonMicrosoftMetaAppleTCS