From 51fc3a4ffbefcdf240b05d0c22a34c46a6331556 Mon Sep 17 00:00:00 2001
From: Bauke <me@bauke.xyz>
Date: Sat, 9 Apr 2022 00:32:20 +0200
Subject: [PATCH] Solve valid-palindrome.

---
 source/lib.rs                  |  1 +
 source/valid_palindrome/mod.rs | 14 ++++++++++++++
 tests/valid_palindrome.rs      | 11 +++++++++++
 3 files changed, 26 insertions(+)
 create mode 100644 source/valid_palindrome/mod.rs
 create mode 100644 tests/valid_palindrome.rs

diff --git a/source/lib.rs b/source/lib.rs
index d011a51..3c40e85 100644
--- a/source/lib.rs
+++ b/source/lib.rs
@@ -9,4 +9,5 @@ pub mod reverse_integer;
 pub mod roman_to_integer;
 pub mod two_sum;
 pub mod valid_anagram;
+pub mod valid_palindrome;
 pub mod valid_parenthesis;
diff --git a/source/valid_palindrome/mod.rs b/source/valid_palindrome/mod.rs
new file mode 100644
index 0000000..3b534a2
--- /dev/null
+++ b/source/valid_palindrome/mod.rs
@@ -0,0 +1,14 @@
+pub fn is_palindrome(string: String) -> bool {
+  let normalized = string.chars().filter_map(|c| {
+    if char::is_alphanumeric(c) {
+      Some(c.to_ascii_lowercase())
+    } else {
+      None
+    }
+  });
+
+  let regular = normalized.clone().collect::<String>();
+  let reversed = normalized.rev().collect::<String>();
+
+  regular == reversed
+}
diff --git a/tests/valid_palindrome.rs b/tests/valid_palindrome.rs
new file mode 100644
index 0000000..bb22cc2
--- /dev/null
+++ b/tests/valid_palindrome.rs
@@ -0,0 +1,11 @@
+use leetcode::valid_palindrome::is_palindrome;
+
+use test_case::test_case;
+
+#[test_case("A man, a plan, a canal: Panama", true; "valid")]
+#[test_case("race a car", false; "invalid")]
+#[test_case("", true; "empty")]
+#[test_case(" \t", true; "whitespace only")]
+fn test_valid_palindrome(input: &str, expected: bool) {
+  assert_eq!(is_palindrome(input.to_string()), expected);
+}