Add problem 2103: Rings and Rods

src/lib.rs

@@ -1434,6 +1434,7 @@ pub mod problem_2090_k_radius_subarray_averages;
 pub mod problem_2091_removing_minimum_and_maximum_from_array;
 pub mod problem_2095_delete_the_middle_node_of_a_linked_list;
 pub mod problem_2099_find_subsequence_of_length_k_with_the_largest_sum;
+pub mod problem_2103_rings_and_rods;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2103_rings_and_rods/iterative.rs

@@ -0,0 +1,40 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    #[allow(clippy::naive_bytecount)] // Not supported by LeetCode.
+    pub fn count_points(rings: String) -> i32 {
+        let mut iter_2 = rings.bytes();
+
+        iter_2.next();
+
+        let mut states = [0_u8; 10];
+
+        for (color, pole) in rings.bytes().zip(iter_2).step_by(2) {
+            states[usize::from(pole) - usize::from(b'0')] |= match color {
+                b'B' => 1,
+                b'G' => 2,
+                _ => 4,
+            };
+        }
+
+        states.iter().filter(|&&x| x == 7).count() as _
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn count_points(rings: String) -> i32 {
+        Self::count_points(rings)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2103_rings_and_rods/mod.rs

@@ -0,0 +1,18 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn count_points(rings: String) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [("B0B6G0R6R0R6G9", 1), ("B0R0G0R9R0B0G0", 1), ("G4", 0)];
+
+        for (rings, expected) in test_cases {
+            assert_eq!(S::count_points(rings.to_string()), expected);
+        }
+    }
+}