Understanding Valid Palindrome
Ignore ASCII punctuation and spaces, compare letters without case, and return whether the remaining letters and digits read the same backward. This exercise accepts ASCII text only.
How it works
A mismatch between mirrored characters rules out a palindrome immediately.
Normalize the input, then move two pointers inward while comparing mirrored characters.
Try an example
Input: s = "A man, a plan, a canal: Panama"
Output: true
The normalized text is "amanaplanacanalpanama".
Constraints
- At most 64 ASCII characters.
- Only letters A–Z, a–z and digits 0–9 participate.
- An empty normalized string is a palindrome.
Use the simulator
Change the input, then choose Visualize input. Use Next and Previous to inspect each decision, or Play to advance automatically. Compare approaches and their complexity. Choose Try yourself to write JavaScript, select My code and Visualize code to inspect its execution, or Run Tests to check results.
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