Add problem 2965: Find Missing and Repeated Values

Author: EFanZh

src/lib.rs

@@ -2031,6 +2031,7 @@ pub mod problem_2958_length_of_longest_subarray_with_at_most_k_frequency;
 pub mod problem_2960_count_tested_devices_after_test_operations;
 pub mod problem_2961_double_modular_exponentiation;
 pub mod problem_2962_count_subarrays_where_max_element_appears_at_least_k_times;
+pub mod problem_2965_find_missing_and_repeated_values;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2965_find_missing_and_repeated_values/mathematical.rs

@@ -0,0 +1,48 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn find_missing_and_repeated_values(grid: Vec<Vec<i32>>) -> Vec<i32> {
+        let n = (grid.len() as u32).pow(2);
+        let mut sum = 0;
+        let mut square_sum = 0;
+
+        grid.into_iter().flatten().for_each(|value| {
+            sum += value;
+            square_sum += i64::from(value.cast_unsigned().pow(2));
+        });
+
+        let expected_sum = n * (1 + n) / 2;
+
+        let expected_square_sum = {
+            let n = u64::from(n);
+
+            n * (1 + n) * (2 * n + 1) / 6
+        };
+
+        let a_minus_b = sum - expected_sum.cast_signed();
+        let a_squared_minus_b_squared = (square_sum - expected_square_sum.cast_signed()) as i32;
+        let a_plus_b = a_squared_minus_b_squared / a_minus_b;
+        let a = (a_minus_b + a_plus_b) >> 1;
+        let b = a_plus_b - a;
+
+        vec![a, b]
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn find_missing_and_repeated_values(grid: Vec<Vec<i32>>) -> Vec<i32> {
+        Self::find_missing_and_repeated_values(grid)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2965_find_missing_and_repeated_values/mod.rs

@@ -0,0 +1,22 @@
+pub mod mathematical;
+
+pub trait Solution {
+    fn find_missing_and_repeated_values(grid: Vec<Vec<i32>>) -> Vec<i32>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+    use crate::test_utilities::Matrix;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (&[[1, 3], [2, 2]] as &dyn Matrix<_>, [2, 4]),
+            (&[[9, 1, 7], [8, 9, 2], [3, 4, 6]], [9, 5]),
+        ];
+
+        for (grid, expected) in test_cases {
+            assert_eq!(S::find_missing_and_repeated_values(grid.to_vec()), expected);
+        }
+    }
+}