3. Palindrome Sentence
easystringtwo pointers
A sentence is a palindrome if, after lowercasing and keeping only letters and digits, it reads the same forwards and backwards.
Return true if s is a palindrome sentence.
Example 1
Inputs = "A man, a plan, a canal: Panama"
Outputtrue
Example 2
Inputs = "race a car"
Outputfalse
Example 3
Inputs = " "
Outputtrue
Constraints
- 1 ≤ s.length ≤ 2·10⁵
- s consists of printable ASCII characters