Add problem 3146: Permutation Difference between Two Strings

Author: EFanZh

src/lib.rs

@@ -2105,6 +2105,7 @@ pub mod problem_3137_minimum_number_of_operations_to_make_word_k_periodic;
 pub mod problem_3138_minimum_length_of_anagram_concatenation;
 pub mod problem_3142_check_if_grid_satisfies_conditions;
 pub mod problem_3143_maximum_points_inside_the_square;
+pub mod problem_3146_permutation_difference_between_two_strings;
 pub mod problem_3350_adjacent_increasing_subarrays_detection_ii;
 
 #[cfg(test)]

src/problem_3146_permutation_difference_between_two_strings/greedy.rs

@@ -0,0 +1,44 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    fn get_indices(s: &str) -> [u8; 26] {
+        let mut result = [0; 26];
+
+        (1..)
+            .zip(s.bytes())
+            .for_each(|(i, c)| result[usize::from(c) - usize::from(b'a')] = i);
+
+        result
+    }
+
+    pub fn find_permutation_difference(s: String, t: String) -> i32 {
+        let s_indices = Self::get_indices(&s);
+        let t_indices = Self::get_indices(&t);
+
+        drop((s, t));
+
+        s_indices
+            .iter()
+            .zip(&t_indices)
+            .map(|(&i, &j)| i32::from(j.abs_diff(i)))
+            .sum()
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn find_permutation_difference(s: String, t: String) -> i32 {
+        Self::find_permutation_difference(s, t)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_3146_permutation_difference_between_two_strings/mod.rs

@@ -0,0 +1,18 @@
+pub mod greedy;
+
+pub trait Solution {
+    fn find_permutation_difference(s: String, t: String) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [(("abc", "bac"), 2), (("abcde", "edbac"), 12)];
+
+        for ((s, t), expected) in test_cases {
+            assert_eq!(S::find_permutation_difference(s.to_string(), t.to_string()), expected);
+        }
+    }
+}