easy

Valid Palindrome

For an ASCII string s, ignore non-alphanumeric characters and letter case. Return whether the remaining characters read the same in both directions. The empty normalized string is a palindrome.

Constraints

0 ≤ length ≤ 200000
ASCII input only

Examples

in: ["Was it a car or a cat I saw?"]

out: true

Ignore ASCII punctuation and case

in: ["coding"]

out: false

Not a palindrome

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Public test cases · contract v1

Arguments are passed to your function. Tests are public practice checks, not hidden interview grading. Passing does not prove every possible input.

Ignore ASCII punctuation and case

["Was it a car or a cat I saw?"] → true

Not a palindrome
```
["coding"] → false
```
Only punctuation
```
[".,!?"] → true
```
Digits matter
```
["0P"] → false
```
Empty
```
[""] → true
```

Hints:

Which approach applies?

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