add initial data

0005-longest-palindromic-substring/src/main.rs

@@ -0,0 +1,64 @@
+fn main() {
+    println!("Hello, world!");
+}
+
+pub fn longest_palindrome(s: String) -> String {
+    let mut best = Vec::with_capacity(s.len());
+
+    let bytes = s.as_bytes();
+
+    for center in 0..bytes.len() {
+        for (mut left_idx, mut right_idx) in [(center, center), (center, center + 1)] {
+            expand(bytes, &mut left_idx, &mut right_idx);
+
+            if right_idx - left_idx > best.len() {
+                best = bytes[left_idx..right_idx].into();
+            }
+        }
+    }
+    String::from_utf8(best).unwrap()
+}
+
+fn expand(bytes: &[u8], left_idx: &mut usize, right_idx: &mut usize) {
+    loop {
+        if bytes.get(*right_idx).is_none_or(|&r| bytes[*left_idx] != r) {
+            *left_idx += 1;
+            return;
+        }
+        match left_idx.checked_sub(1) {
+            Some(new_left) => *left_idx = new_left,
+            None => {
+                *right_idx += 1;
+                return;
+            }
+        }
+        *right_idx += 1;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::longest_palindrome;
+
+    #[test]
+    fn test_1() {
+        assert!(
+            ["aba".to_string(), "bab".to_string()]
+                .contains(&longest_palindrome("babad".to_string()))
+        );
+    }
+    #[test]
+    fn test_2() {
+        assert_eq!(longest_palindrome("cbbd".to_string()), "bb".to_string());
+    }
+
+    #[test]
+    fn test_3() {
+        assert_eq!(longest_palindrome("whdqcudjpisufnrtsyupwtnnbsvfptrcgvobbjglmpynebblpigaflpbezjvjgbmofejyjssdhbgghgrhzuplbeptpaecfdanhlylgusptlgobkqnulxvnwuzwauewcplnvcwowmbxxnhsdmgxtvbfgnuqdpxennqglgmspbagvmjcmzmbsuacxlqfxjggrwsnbblnnwisvmpwwhomyjylbtedzrptejjsaiqzprnadkjxeqfdpkddmbzokkegtypxaafodjdwirynzurzkjzrkufsokhcdkajwmqvhcbzcnysrbsfxhfvtodqabvbuosxtonbpmgoemcgkudandrioncjigbyizekiakmrfjvezuzddjxqyevyenuebfwugqelxwpirsoyixowcmtgosuggrkdciehktojageynqkazsqxraimeopcsjxcdtzhlbvtlvzytgblwkmbfwmggrkpioeofkrmfdgfwknrbaimhefpzckrzwdvddhdqujffwvtvfyjlimkljrsnnhudyejcrtrwvtsbkxaplchgbikscfcbhovlepdojmqybzhbiionyjxqsmquehkhzdiawfxunguhqhkxqdiiwsbuhosebxrpcstpklukjcsnnzpbylzaoyrmyjatuovmaqiwfdfwyhugbeehdzeozdrvcvghekusiahfxhlzclhbegdnvkzeoafodnqbtanfwixjzirnoaiqamjgkcapeopbzbgtxsjhqurbpbuduqjziznblrhxbydxsmtjdfeepntijqpkuwmqezkhnkwbvwgnkxmkyhlbfuwaslmjzlhocsgtoujabbexvxweigplmlewumcone".to_string()), "wfdfw".to_string());
+    }
+
+    #[test]
+    fn test_4() {
+        assert_eq!(longest_palindrome("a".to_string()), "a".to_string());
+    }
+}