From ddfffac29d7a49547c8c568236e4d2f69bd50fbb Mon Sep 17 00:00:00 2001
From: EFanZh <efanzh@gmail.com>
Date: Thu, 4 Jul 2024 21:45:23 +0800
Subject: [PATCH] Add problem 2256: Minimum Average Difference

---
 src/lib.rs                                    |  1 +
 .../iterative.rs                              | 55 +++++++++++++++++++
 .../mod.rs                                    | 18 ++++++
 3 files changed, 74 insertions(+)
 create mode 100644 src/problem_2256_minimum_average_difference/iterative.rs
 create mode 100644 src/problem_2256_minimum_average_difference/mod.rs

diff --git a/src/lib.rs b/src/lib.rs
index 5c5b17fc..10dca8ec 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1581,6 +1581,7 @@ pub mod problem_2243_calculate_digit_sum_of_a_string;
 pub mod problem_2244_minimum_rounds_to_complete_all_tasks;
 pub mod problem_2248_intersection_of_multiple_arrays;
 pub mod problem_2255_count_prefixes_of_a_given_string;
+pub mod problem_2256_minimum_average_difference;
 pub mod problem_2259_remove_digit_from_number_to_maximize_result;
 pub mod problem_2260_minimum_consecutive_cards_to_pick_up;
 pub mod problem_2262_total_appeal_of_a_string;
diff --git a/src/problem_2256_minimum_average_difference/iterative.rs b/src/problem_2256_minimum_average_difference/iterative.rs
new file mode 100644
index 00000000..ef904090
--- /dev/null
+++ b/src/problem_2256_minimum_average_difference/iterative.rs
@@ -0,0 +1,55 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn minimum_average_difference(nums: Vec<i32>) -> i32 {
+        let mut left_sum = 0;
+        let mut left_count = 0;
+        let mut right_sum = nums.iter().fold(0_u64, |sum, &x| sum + u64::from(x as u32));
+        let mut right_count = nums.len() as u64;
+        let mut min_diff = u64::MAX;
+        let mut min_diff_index = 0;
+
+        for num in nums {
+            let num = u64::from(num as u32);
+
+            left_count += 1;
+            right_count -= 1;
+            left_sum += num;
+            right_sum -= num;
+
+            let left_average = left_sum / left_count;
+            let right_average = if right_count == 0 { 0 } else { right_sum / right_count };
+
+            let diff = left_average.abs_diff(right_average);
+
+            if diff < min_diff {
+                min_diff = diff;
+                min_diff_index = left_count;
+
+                if diff == 0 {
+                    break;
+                }
+            }
+        }
+
+        (min_diff_index - 1) as _
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn minimum_average_difference(nums: Vec<i32>) -> i32 {
+        Self::minimum_average_difference(nums)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}
diff --git a/src/problem_2256_minimum_average_difference/mod.rs b/src/problem_2256_minimum_average_difference/mod.rs
new file mode 100644
index 00000000..6a4778d2
--- /dev/null
+++ b/src/problem_2256_minimum_average_difference/mod.rs
@@ -0,0 +1,18 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn minimum_average_difference(nums: Vec<i32>) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [(&[2, 5, 3, 9, 5, 3] as &[_], 3), (&[0], 0)];
+
+        for (nums, expected) in test_cases {
+            assert_eq!(S::minimum_average_difference(nums.to_vec()), expected);
+        }
+    }
+}