Exercise 3: Palindrome Checker - Hints

Hint 1: Cleaning the string

First, filter to keep only alphanumeric characters and convert to lowercase:

#![allow(unused)]
fn main() {
let cleaned: String = s.chars()
    .filter(|c| c.is_alphanumeric())
    .flat_map(|c| c.to_lowercase())
    .collect();
}

Hint 2: Comparing forward and backward

Once cleaned, compare the string with its reverse:

#![allow(unused)]
fn main() {
let reversed: String = cleaned.chars().rev().collect();
cleaned == reversed
}

Hint 3: More efficient approach

For a solution with single allocation:

#![allow(unused)]
fn main() {
let chars: Vec<char> = s.chars()
    .filter(|c| c.is_alphanumeric())
    .flat_map(|c| c.to_lowercase())
    .collect();

chars.iter().eq(chars.iter().rev())
}

Hint 4: Why chars() not bytes()?

Use chars() instead of bytes() to handle Unicode correctly:

• "café".bytes() → 5 bytes (é is multi-byte)
• "café".chars() → 4 characters