Add problem 3212: Count Submatrices With Equal Frequency of X and Y

Author: EFanZh

src/lib.rs

@@ -2139,6 +2139,7 @@ pub mod problem_3206_alternating_groups_i;
 pub mod problem_3208_alternating_groups_ii;
 pub mod problem_3210_find_the_encrypted_string;
 pub mod problem_3211_generate_binary_strings_without_adjacent_zeros;
+pub mod problem_3212_count_submatrices_with_equal_frequency_of_x_and_y;
 pub mod problem_3350_adjacent_increasing_subarrays_detection_ii;
 
 #[cfg(test)]

src/problem_3212_count_submatrices_with_equal_frequency_of_x_and_y/dynamic_programming.rs

@@ -0,0 +1,67 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn number_of_submatrices(grid: Vec<Vec<char>>) -> i32 {
+        const X: u32 = 'X' as _;
+        const Y: u32 = 'Y' as _;
+
+        let mut iter = grid
+            .into_iter()
+            .map(|row| row.into_iter().map(u32::from).collect::<Vec<_>>());
+
+        iter.next().map_or(0, |mut cache| {
+            let mut result = 0;
+            let mut total_x = 0;
+            let mut total_y = 0;
+
+            for state in &mut cache {
+                *state = match *state {
+                    X => 1 << 16,
+                    Y => 1,
+                    _ => 0,
+                };
+
+                total_x += *state >> 16;
+                total_y += *state & 0x_ffff;
+                result += i32::from(total_x == total_y && total_x != 0);
+            }
+
+            for row in iter {
+                total_x = 0;
+                total_y = 0;
+
+                cache.iter_mut().zip(row).for_each(|(state, value)| {
+                    *state += match value {
+                        X => 1 << 16,
+                        Y => 1,
+                        _ => 0,
+                    };
+
+                    total_x += *state >> 16;
+                    total_y += *state & 0x_ffff;
+                    result += i32::from(total_x == total_y && total_x != 0);
+                });
+            }
+
+            result
+        })
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn number_of_submatrices(grid: Vec<Vec<char>>) -> i32 {
+        Self::number_of_submatrices(grid)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_3212_count_submatrices_with_equal_frequency_of_x_and_y/mod.rs

@@ -0,0 +1,21 @@
+pub mod dynamic_programming;
+
+pub trait Solution {
+    fn number_of_submatrices(grid: Vec<Vec<char>>) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [(&["XY.", "Y.."] as &[_], 3), (&["XX", "XY"], 0), (&["..", ".."], 0)];
+
+        for (grid, expected) in test_cases {
+            assert_eq!(
+                S::number_of_submatrices(grid.iter().map(|row| row.chars().collect()).collect()),
+                expected,
+            );
+        }
+    }
+}