## 125. Valid Palindrome

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

Note: For the purpose of this problem, we define empty string as valid palindrome.

Example 1:

```Input: "A man, a plan, a canal: Panama"
Output: true
```

Example 2:

```Input: "race a car"
Output: false
```

Constraints:

• `s` consists only of printable ASCII characters.

## Rust Solution

``````struct Solution;

impl Solution {
fn is_palindrome(s: String) -> bool {
let s: Vec<char> = s
.chars()
.filter(|c| c.is_ascii_alphanumeric())
.map(|c| c.to_ascii_lowercase())
.collect();
let a: String = s.iter().collect();
let b: String = s.iter().rev().collect();
a == b
}
}

#[test]
fn test() {
let s = "A man, a plan, a canal: Panama".to_string();
let res = true;
assert_eq!(Solution::is_palindrome(s), res);
let s = "race a car".to_string();
let res = false;
assert_eq!(Solution::is_palindrome(s), res);
}
``````

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