Add problem 0393: UTF-8 Validation

src/lib.rs

@@ -294,6 +294,7 @@ pub mod problem_0387_first_unique_character_in_a_string;
 pub mod problem_0389_find_the_difference;
 pub mod problem_0390_elimination_game;
 pub mod problem_0392_is_subsequence;
+pub mod problem_0393_utf_8_validation;
 pub mod problem_0394_decode_string;
 pub mod problem_0396_rotate_function;
 pub mod problem_0397_integer_replacement;

src/problem_0393_utf_8_validation/iterative.rs

@@ -0,0 +1,38 @@
+pub struct Solution;
+
+impl Solution {
+    pub fn valid_utf8(data: Vec<i32>) -> bool {
+        let mut idx = 0;
+        let mut count = 0;
+        while idx < data.len() && count >= 0 {
+            let bits = (data[idx] & 0b1111_1000) >> 3;
+            let ones = [0b10000, 0b01000, 0b00100, 0b00010, 0b00001]
+                .into_iter()
+                .map(|mask| bits & mask)
+                .take_while(|&x| x != 0)
+                .count() as i32;
+            match ones {
+                0 if count == 0 => (),
+                1 => count -= 1,
+                2..=4 if count == 0 => count = ones - 1,
+                _ => return false,
+            }
+            idx += 1;
+        }
+        count == 0
+    }
+}
+
+impl super::Solution for Solution {
+    fn valid_utf8(data: Vec<i32>) -> bool {
+        Self::valid_utf8(data)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_0393_utf_8_validation/mod.rs

@@ -0,0 +1,29 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn valid_utf8(data: Vec<i32>) -> bool;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (&[197, 130, 1] as &[_], true),
+            (&[235, 140, 4], false),
+            (
+                &[206, 210, 189, 208, 197, 163, 182, 171, 212, 243, 10, 0, 10],
+                false,
+            ),
+            (&[230, 136, 145], true),
+            (&[240, 162, 138, 147], true),
+            (&[240, 255], false),
+            (&[255], false),
+        ];
+
+        for (data, expected) in test_cases {
+            assert_eq!(S::valid_utf8(data.to_vec()), expected);
+        }
+    }
+}