Add problem 2379: Minimum Recolors to Get K Consecutive Black Blocks

Author: EFanZh

src/lib.rs

@@ -1768,6 +1768,7 @@ pub mod problem_2369_check_if_there_is_a_valid_partition_for_the_array;
 pub mod problem_2370_longest_ideal_subsequence;
 pub mod problem_2373_largest_local_values_in_a_matrix;
 pub mod problem_2374_node_with_highest_edge_score;
+pub mod problem_2379_minimum_recolors_to_get_k_consecutive_black_blocks;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2379_minimum_recolors_to_get_k_consecutive_black_blocks/mod.rs

@@ -0,0 +1,19 @@
+pub mod sliding_window;
+pub mod sliding_window_2;
+
+pub trait Solution {
+    fn minimum_recolors(blocks: String, k: i32) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [(("WBBWWBBWBW", 7), 3), (("WBWBBBW", 2), 0)];
+
+        for ((blocks, k), expected) in test_cases {
+            assert_eq!(S::minimum_recolors(blocks.to_string(), k), expected);
+        }
+    }
+}

src/problem_2379_minimum_recolors_to_get_k_consecutive_black_blocks/sliding_window.rs

@@ -0,0 +1,36 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn minimum_recolors(blocks: String, k: i32) -> i32 {
+        let blocks = blocks.as_bytes();
+        let (left, right) = blocks.split_at(k as u32 as _);
+        let mut white_count = left.iter().fold(0, |count, &c| count + u8::from(c == b'W'));
+        let mut result = white_count;
+
+        for (&old, &new) in blocks.iter().zip(right) {
+            white_count -= u8::from(old == b'W');
+            white_count += u8::from(new == b'W');
+            result = result.min(white_count);
+        }
+
+        i32::from(result)
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn minimum_recolors(blocks: String, k: i32) -> i32 {
+        Self::minimum_recolors(blocks, k)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2379_minimum_recolors_to_get_k_consecutive_black_blocks/sliding_window_2.rs

@@ -0,0 +1,36 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn minimum_recolors(blocks: String, k: i32) -> i32 {
+        let blocks = blocks.as_bytes();
+        let (left, right) = blocks.split_at(k as u32 as usize - 1);
+        let mut white_count = left.iter().fold(0, |count, &c| count + u8::from(c == b'W'));
+        let mut result = u8::MAX;
+
+        for (&old, &c) in blocks.iter().zip(right) {
+            white_count += u8::from(c == b'W');
+            result = result.min(white_count);
+            white_count -= u8::from(old == b'W');
+        }
+
+        i32::from(result)
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn minimum_recolors(blocks: String, k: i32) -> i32 {
+        Self::minimum_recolors(blocks, k)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}