Add problem 2262: Total Appeal of A String

src/lib.rs

@@ -1571,6 +1571,7 @@ pub mod problem_2248_intersection_of_multiple_arrays;
 pub mod problem_2255_count_prefixes_of_a_given_string;
 pub mod problem_2259_remove_digit_from_number_to_maximize_result;
 pub mod problem_2260_minimum_consecutive_cards_to_pick_up;
+pub mod problem_2262_total_appeal_of_a_string;
 pub mod problem_2264_largest_3_same_digit_number_in_string;
 pub mod problem_2265_count_nodes_equal_to_average_of_subtree;
 pub mod problem_2266_count_number_of_texts;

src/problem_2262_total_appeal_of_a_string/dynamic_programming.rs

@@ -0,0 +1,38 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+use std::mem;
+
+impl Solution {
+    pub fn appeal_sum(s: String) -> i64 {
+        let mut prev_indices = [0_u32; 26];
+        let mut i = 0;
+        let mut result = 0_u64;
+        let mut appeal = 0;
+
+        for c in s.into_bytes() {
+            i += 1;
+            appeal += i - mem::replace(&mut prev_indices[usize::from(c) - usize::from(b'a')], i);
+            result += u64::from(appeal);
+        }
+
+        result as _
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn appeal_sum(s: String) -> i64 {
+        Self::appeal_sum(s)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2262_total_appeal_of_a_string/mod.rs

@@ -0,0 +1,18 @@
+pub mod dynamic_programming;
+
+pub trait Solution {
+    fn appeal_sum(s: String) -> i64;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [("abbca", 28), ("code", 20)];
+
+        for (s, expected) in test_cases {
+            assert_eq!(S::appeal_sum(s.to_string()), expected);
+        }
+    }
+}