Add problem 848: Shifting Letters

Author: EFanZh

src/lib.rs

@@ -692,6 +692,7 @@ pub mod problem_0841_keys_and_rooms;
 pub mod problem_0844_backspace_string_compare;
 pub mod problem_0845_longest_mountain_in_array;
 pub mod problem_0846_hand_of_straights;
+pub mod problem_0848_shifting_letters;
 pub mod problem_0867_transpose_matrix;
 pub mod problem_1143_longest_common_subsequence;
 pub mod problem_1192_critical_connections_in_a_network;

src/problem_0848_shifting_letters/iterative.rs

@@ -0,0 +1,38 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn shifting_letters(s: String, shifts: Vec<i32>) -> String {
+        let mut s = s.into_bytes();
+        let mut shift = 0;
+
+        for (c, &extra_shift) in s.iter_mut().zip(&shifts).rev() {
+            shift = ((u32::from(shift) + extra_shift as u32) % 26) as u8;
+
+            *c += shift;
+
+            if *c > b'z' {
+                *c -= 26;
+            }
+        }
+
+        String::from_utf8(s).unwrap()
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn shifting_letters(s: String, shifts: Vec<i32>) -> String {
+        Self::shifting_letters(s, shifts)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_0848_shifting_letters/mod.rs

@@ -0,0 +1,22 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn shifting_letters(s: String, shifts: Vec<i32>) -> String;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (("abc", &[3, 5, 9] as &[_]), "rpl"),
+            (("aaa", &[1, 2, 3]), "gfd"),
+            (("ruu", &[26, 9, 17]), "rul"),
+        ];
+
+        for ((s, shifts), expected) in test_cases {
+            assert_eq!(S::shifting_letters(s.to_string(), shifts.to_vec()), expected);
+        }
+    }
+}