Add problem 2125: Number of Laser Beams in a Bank

src/lib.rs

@@ -1526,6 +1526,7 @@ pub mod problem_2114_maximum_number_of_words_found_in_sentences;
 pub mod problem_2116_check_if_a_parentheses_string_can_be_valid;
 pub mod problem_2119_a_number_after_a_double_reversal;
 pub mod problem_2124_check_if_all_as_appears_before_all_bs;
+pub mod problem_2125_number_of_laser_beams_in_a_bank;
 pub mod problem_2129_capitalize_the_title;
 pub mod problem_2130_maximum_twin_sum_of_a_linked_list;
 pub mod problem_2131_longest_palindrome_by_concatenating_two_letter_words;

src/problem_2125_number_of_laser_beams_in_a_bank/iterative.rs

@@ -0,0 +1,44 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn number_of_beams(bank: Vec<String>) -> i32 {
+        let mut result = 0;
+        let mut prev = 0;
+
+        for bank in bank {
+            let offset = (u32::from(b'0') * bank.len() as u32).wrapping_neg();
+
+            let devices = bank
+                .as_bytes()
+                .iter()
+                .fold(offset, |sum, &c| sum.wrapping_add(u32::from(c)));
+
+            drop(bank);
+
+            if devices != 0 {
+                result += prev * devices;
+                prev = devices;
+            }
+        }
+
+        result as _
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn number_of_beams(bank: Vec<String>) -> i32 {
+        Self::number_of_beams(bank)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2125_number_of_laser_beams_in_a_bank/mod.rs

@@ -0,0 +1,24 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn number_of_beams(bank: Vec<String>) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (&["011001", "000000", "010100", "001000"] as &[_], 8),
+            (&["000", "111", "000"], 0),
+        ];
+
+        for (bank, expected) in test_cases {
+            assert_eq!(
+                S::number_of_beams(bank.iter().copied().map(str::to_string).collect()),
+                expected,
+            );
+        }
+    }
+}