sort: Add benchmark for shell sort

sort/Cargo.toml

@@ -24,4 +24,8 @@ harness = false
 
 [[bench]]
 name = "selection_sort"
-harness = false
+harness = false
+
+[[bench]]
+name = "shell_sort"
+harness = false

sort/benches/shell_sort.rs

@@ -0,0 +1,37 @@
+// Copyright (c) 2024 Xu Shaohua <[email protected]>. All rights reserved.
+// Use of this source is governed by General Public License that can be found
+// in the LICENSE file.
+
+use criterion::{criterion_group, criterion_main, Criterion};
+
+use sort::shell_sort::shell_sort;
+use sort::util::random_ints;
+
+fn criterion_benchmark(c: &mut Criterion) {
+    for exp in 1..5 {
+        let len: usize = 2 * 10_usize.pow(exp);
+        let arr = random_ints(len).expect("Failed to generate random integers");
+        let title1 = format!("std_sort_for_shell_sort {len}");
+        let title2 = format!("shell_sort {len}");
+        let mut arr_sorted = arr.clone();
+        arr_sorted.sort();
+
+        c.bench_function(&title1, |b| {
+            b.iter(|| {
+                let mut arr1 = arr.clone();
+                arr1.sort();
+                assert_eq!(arr1, arr_sorted);
+            })
+        });
+        c.bench_function(&title2, |b| {
+            b.iter(|| {
+                let mut arr2 = arr.clone();
+                shell_sort(&mut arr2);
+                assert_eq!(arr2, arr_sorted);
+            })
+        });
+    }
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);

src/array/sort/shell-sort.md

@@ -29,4 +29,5 @@
 
 - 最差情况下的时间复杂度 `O(N^2)`, 空间复杂度是 `O(1)`
 - 最好情竞下的时间复杂度是 `Ω(N log(N))`
+- 比插入排序快
 - 与插入排序不同的时, 希尔排序适合大中型的数组, 对于任意顺序的数组也有效