loose constrain on generic arg

Author: douchuan

benches/sort.rs

@@ -107,7 +107,7 @@ fn eq_data_merge_v2(b: &mut Bencher) {
 fn small_merge_v3(b: &mut Bencher) {
     b.iter(|| {
         let mut numbs = [1, 2, 4, 8, 9, 9, 13, 17, 22];
-        let f = |x: i32, y: i32| x > y;
+        let f = |x: &i32, y: &i32| x > y;
         sort::merge::v3::sort(&mut numbs, &f);
     });
 }
@@ -117,7 +117,7 @@ fn large_merge_v3(b: &mut Bencher) {
     let data = util::random_data(util::DATA_LEN);
     b.iter(|| {
         let mut numbs = data.clone();
-        let f = |x: i32, y: i32| x > y;
+        let f = |x: &i32, y: &i32| x > y;
         sort::merge::v3::sort(&mut numbs, &f);
     });
 }
@@ -127,7 +127,7 @@ fn large_sorted_asc_merge_v3(b: &mut Bencher) {
     let data = util::sorted_data_asc(util::DATA_LEN);
     b.iter(|| {
         let mut numbs = data.clone();
-        let f = |x: i32, y: i32| x > y;
+        let f = |x: &i32, y: &i32| x > y;
         sort::merge::v3::sort(&mut numbs, &f);
     });
 }
@@ -137,7 +137,7 @@ fn large_sorted_desc_merge_v3(b: &mut Bencher) {
     let data = util::sorted_data_desc(util::DATA_LEN);
     b.iter(|| {
         let mut numbs = data.clone();
-        let f = |x: i32, y: i32| x > y;
+        let f = |x: &i32, y: &i32| x > y;
         sort::merge::v3::sort(&mut numbs, &f);
     });
 }
@@ -147,7 +147,7 @@ fn eq_data_merge_v3(b: &mut Bencher) {
     let data = util::eq_data(util::DATA_LEN);
     b.iter(|| {
         let mut numbs = data.clone();
-        let f = |x: i32, y: i32| x > y;
+        let f = |x: &i32, y: &i32| x > y;
         sort::merge::v3::sort(&mut numbs, &f);
     });
 }

src/sort/insert.rs

@@ -4,15 +4,14 @@
 
 pub fn sort<T, F>(a: &mut [T], compare: F)
 where
-    T: Copy,
-    F: Fn(T, T) -> bool,
+    F: Fn(&T, &T) -> bool,
 {
     let len = a.len();
     // 注意起始索引
     for i in 1..len {
         // 将a[i]插入到a[i-1]，a[i-2]，a[i-3]……之中
         let mut j = i;
-        while j > 0 && compare(a[j], a[j - 1]) {
+        while j > 0 && compare(&a[j], &a[j - 1]) {
             a.swap(j, j - 1);
             j -= 1;
         }

src/sort/merge.rs

@@ -72,7 +72,6 @@ pub mod v1 {
 }
 
 pub mod v2 {
-    use std::fmt::Debug;
     use std::ptr;
 
     //ws为辅助space
@@ -124,7 +123,7 @@ pub mod v2 {
 
     pub fn sort<T, F>(a: &mut [T], compare: &F)
     where
-        T: Copy + Default + Debug,
+        T: Copy + Default,
         F: Fn(T, T) -> bool,
     {
         let len = a.len();
@@ -148,11 +147,10 @@ pub mod v3 {
         compare: &F,
         mut w: usize,
     ) where
-        T: Copy,
-        F: Fn(T, T) -> bool,
+        F: Fn(&T, &T) -> bool,
     {
         while i < m && j < n {
-            if compare(xs[i], xs[j]) {
+            if compare(&xs[i], &xs[j]) {
                 xs.swap(w, i);
                 i += 1;
             } else {
@@ -179,8 +177,7 @@ pub mod v3 {
     /// constraint, len(w) == u - l
     fn wsort<T, F>(xs: &mut [T], mut l: usize, u: usize, compare: &F, mut w: usize)
     where
-        T: Copy,
-        F: Fn(T, T) -> bool,
+        F: Fn(&T, &T) -> bool,
     {
         if u - l > 1 {
             let m = (u + l) / 2;
@@ -198,8 +195,7 @@ pub mod v3 {
 
     fn do_sort<T, F>(a: &mut [T], l: usize, u: usize, compare: &F)
     where
-        T: Copy,
-        F: Fn(T, T) -> bool,
+        F: Fn(&T, &T) -> bool,
     {
         if u - l > 1 {
             let mut m = (u + l) / 2;
@@ -218,7 +214,7 @@ pub mod v3 {
             let mut n = w;
             while n > l {
                 m = n;
-                while m < u && compare(a[m], a[m - 1]) {
+                while m < u && compare(&a[m], &a[m - 1]) {
                     a.swap(m, m - 1);
                     m += 1;
                 }
@@ -229,8 +225,7 @@ pub mod v3 {
 
     pub fn sort<T, F>(a: &mut [T], compare: &F)
     where
-        T: Copy,
-        F: Fn(T, T) -> bool,
+        F: Fn(&T, &T) -> bool,
     {
         let len = a.len();
         do_sort(a, 0, len, compare);

src/sort/selection.rs

@@ -7,7 +7,7 @@
 
 pub fn sort<T>(a: &mut [T])
 where
-    T: Copy + std::cmp::PartialOrd,
+    T: std::cmp::PartialOrd,
 {
     let len = a.len();
     for i in 0..len {
@@ -27,7 +27,7 @@ where
 /// 最大值放到末尾
 pub fn sort_cocktail<T>(a: &mut [T])
 where
-    T: Copy + std::cmp::PartialOrd,
+    T: std::cmp::PartialOrd,
 {
     let n = a.len();
     let semi_n = n / 2;

src/sort/shell.rs

@@ -4,11 +4,9 @@
 //! 是直接插入排序算法的一种更高效的改进版本。希尔排序是
 //! 非稳定排序算法。该方法因 D.L.Shell 于 1959 年提出而得名。
 
-use std::fmt::Debug;
-
 pub fn sort<T, F>(a: &mut [T], compare: F)
 where
-    T: Copy + Default + Debug,
+    T: Copy,
     F: Fn(T, T) -> bool,
 {
     let len = a.len();

tests/test_sort.rs

@@ -13,7 +13,7 @@ fn bubble() {
 
 #[test]
 fn insert() {
-    let test = |x: i32, y: i32| x < y;
+    let test = |x: &i32, y: &i32| x < y;
     let data = sort::util::plan_data();
     for (t, expect) in data {
         let mut tt = t.clone();
@@ -75,7 +75,7 @@ fn merge_v2() {
 
 #[test]
 fn merge_v3() {
-    let test = |x: i32, y: i32| x < y;
+    let test = |x: &i32, y: &i32| x < y;
     let data = sort::util::plan_data();
     for (t, expect) in data {
         let mut tt = t.clone();