Add problem 2381: Shifting Letters II

Author: EFanZh

src/lib.rs

@@ -1770,6 +1770,7 @@ pub mod problem_2373_largest_local_values_in_a_matrix;
 pub mod problem_2374_node_with_highest_edge_score;
 pub mod problem_2379_minimum_recolors_to_get_k_consecutive_black_blocks;
 pub mod problem_2380_time_needed_to_rearrange_a_binary_string;
+pub mod problem_2381_shifting_letters_ii;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2381_shifting_letters_ii/mod.rs

@@ -0,0 +1,24 @@
+pub mod sweep_line;
+
+pub trait Solution {
+    fn shifting_letters(s: String, shifts: Vec<Vec<i32>>) -> String;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (("abc", &[[0, 1, 0], [1, 2, 1], [0, 2, 1]] as &[_]), "ace"),
+            (("dztz", &[[0, 0, 0], [1, 1, 1]]), "catz"),
+        ];
+
+        for ((s, shifts), expected) in test_cases {
+            assert_eq!(
+                S::shifting_letters(s.to_string(), shifts.iter().map(Vec::from).collect()),
+                expected,
+            );
+        }
+    }
+}

src/problem_2381_shifting_letters_ii/sweep_line.rs

@@ -0,0 +1,80 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    fn assign_add(target: &mut u8, value: u8) {
+        *target += value;
+
+        if *target >= 26 {
+            *target -= 26;
+        }
+    }
+
+    fn assign_sub(target: &mut u8, value: u8) {
+        if *target < value {
+            *target += 26;
+        }
+
+        *target -= value;
+    }
+
+    fn helper(slice: &mut [u8], shifts: &[Vec<i32>]) {
+        let mut prev = b'a';
+
+        for offset in &mut *slice {
+            let current = *offset;
+
+            Self::assign_sub(offset, prev);
+
+            prev = current;
+        }
+
+        for shift in shifts {
+            let [start, end, direction]: [_; 3] = shift.as_slice().try_into().ok().unwrap();
+            let diff = if direction == 0 { 25 } else { 1 };
+
+            Self::assign_add(&mut slice[start as u32 as usize], diff);
+
+            if let Some(end) = slice.get_mut(end as u32 as usize + 1) {
+                Self::assign_sub(end, diff);
+            }
+        }
+
+        let mut prev = b'a';
+
+        for target in slice {
+            prev += *target;
+
+            if prev > b'z' {
+                prev -= 26;
+            }
+
+            *target = prev;
+        }
+    }
+
+    pub fn shifting_letters(s: String, shifts: Vec<Vec<i32>>) -> String {
+        let mut buffer = s.into_bytes();
+
+        Self::helper(&mut buffer, &shifts);
+
+        String::from_utf8(buffer).unwrap()
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn shifting_letters(s: String, shifts: Vec<Vec<i32>>) -> String {
+        Self::shifting_letters(s, shifts)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}