From e9201ef326132612b5ed998f3193a024ea4aaacc Mon Sep 17 00:00:00 2001
From: Xu Shaohua <shaohua@biofan.org>
Date: Mon, 20 May 2024 19:11:57 +0800
Subject: [PATCH] sorts: Add unittests for bucket sort

---
 sort/src/bucket_sort.rs   | 45 +++++++++++++++++++++++++++++++++------
 sort/src/counting_sort.rs | 29 +++++++++++++++++++++++++
 sort/src/lib.rs           |  3 ++-
 sort/src/merge_sort.rs    |  2 --
 4 files changed, 70 insertions(+), 9 deletions(-)

diff --git a/sort/src/bucket_sort.rs b/sort/src/bucket_sort.rs
index 1a1151491..8d21aeba3 100644
--- a/sort/src/bucket_sort.rs
+++ b/sort/src/bucket_sort.rs
@@ -3,8 +3,10 @@
 // in the LICENSE file.
 
 pub fn bucket_sort(nums: &mut [i32]) {
-    let bucket_size = nums.len().ilog2() as usize;
-    bucket_sort_with_bucket(nums, bucket_size);
+    if !nums.is_empty() {
+        let bucket_size = nums.len().ilog2() as usize;
+        bucket_sort_with_bucket(nums, bucket_size);
+    }
 }
 
 fn insertion_sort(nums: &mut [i32]) {
@@ -21,14 +23,16 @@ fn insertion_sort(nums: &mut [i32]) {
 
 #[allow(clippy::cast_sign_loss)]
 fn bucket_sort_with_bucket(nums: &mut [i32], bucket_size: usize) {
-    let min_num: i32 = nums.iter().min().copied().unwrap_or_default();
-    let max_num: i32 = nums.iter().max().copied().unwrap_or_default();
-    let bucket_count: usize = ((max_num - min_num) as usize) / bucket_size + 1;
+    let min_num: i32 = nums.iter().min().copied().unwrap();
+    let max_num: i32 = nums.iter().max().copied().unwrap();
+    let range: i32 = max_num - min_num;
+    let bucket_count: usize = range as usize / bucket_size + 1;
     let mut buckets: Vec<Vec<i32>> = vec![vec![]; bucket_count];
 
     // 遍历数组, 将元素分配到每个桶中
     for &num in nums.iter() {
-        let bucket_index = ((num - min_num) as usize) / bucket_size;
+        let range: i32 = num - min_num;
+        let bucket_index: usize = range as usize / bucket_size;
         buckets[bucket_index].push(num);
     }
 
@@ -40,3 +44,32 @@ fn bucket_sort_with_bucket(nums: &mut [i32], bucket_size: usize) {
         index += bucket.len();
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::bucket_sort;
+
+    #[test]
+    fn test_bucket_sort() {
+        let mut list = [0, 5, 3, 2, 2];
+        bucket_sort(&mut list);
+        assert_eq!(list, [0, 2, 2, 3, 5]);
+
+        let mut list = [-2, -5, -45];
+        bucket_sort(&mut list);
+        assert_eq!(list, [-45, -5, -2]);
+
+        let mut list = [
+            -998_166, -996_360, -995_703, -995_238, -995_066, -994_740, -992_987, -983_833,
+            -987_905, -980_069, -977_640,
+        ];
+        bucket_sort(&mut list);
+        assert_eq!(
+            list,
+            [
+                -998_166, -996_360, -995_703, -995_238, -995_066, -994_740, -992_987, -987_905,
+                -983_833, -980_069, -977_640,
+            ]
+        );
+    }
+}
diff --git a/sort/src/counting_sort.rs b/sort/src/counting_sort.rs
index d8b685196..b91a511fd 100644
--- a/sort/src/counting_sort.rs
+++ b/sort/src/counting_sort.rs
@@ -88,3 +88,32 @@ pub fn counting_sort(nums: &mut [i32]) {
         //counts[index] -= 1;
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::counting_sort;
+
+    #[test]
+    fn test_counting_sort() {
+        let mut list = [0, 5, 3, 2, 2];
+        counting_sort(&mut list);
+        assert_eq!(list, [0, 2, 2, 3, 5]);
+
+        let mut list = [-2, -5, -45];
+        counting_sort(&mut list);
+        assert_eq!(list, [-45, -5, -2]);
+
+        let mut list = [
+            -998_166, -996_360, -995_703, -995_238, -995_066, -994_740, -992_987, -983_833,
+            -987_905, -980_069, -977_640,
+        ];
+        counting_sort(&mut list);
+        assert_eq!(
+            list,
+            [
+                -998_166, -996_360, -995_703, -995_238, -995_066, -994_740, -992_987, -987_905,
+                -983_833, -980_069, -977_640,
+            ]
+        );
+    }
+}
diff --git a/sort/src/lib.rs b/sort/src/lib.rs
index 6966b380c..bc3d7ece0 100644
--- a/sort/src/lib.rs
+++ b/sort/src/lib.rs
@@ -23,7 +23,6 @@ mod quick_sort;
 mod selection_sort;
 mod shaker_sort;
 mod shell_sort;
-pub mod util;
 
 pub use bubble_sort::bubble_sort;
 pub use bucket_sort::bucket_sort;
@@ -37,3 +36,5 @@ pub use quick_sort::quick_sort;
 pub use selection_sort::selection_sort;
 pub use shaker_sort::shaker_sort;
 pub use shell_sort::shell_sort;
+
+pub mod util;
diff --git a/sort/src/merge_sort.rs b/sort/src/merge_sort.rs
index cbc14d39b..075b24ba8 100644
--- a/sort/src/merge_sort.rs
+++ b/sort/src/merge_sort.rs
@@ -30,7 +30,6 @@ fn sort<T>(arr: &mut [T], low: usize, high: usize)
 where
     T: PartialOrd + Copy,
 {
-    println!("low: {low}, high: {high}");
     if low >= high {
         return;
     }
@@ -62,7 +61,6 @@ fn merge<T>(arr: &mut [T], low: usize, middle: usize, high: usize)
 where
     T: PartialOrd + Copy,
 {
-    println!("merge: low: {low}, middle: {middle}, high: {high}");
     let aux = arr[0..=high].to_vec();
 
     // Merge back to arr.