Rust排序算法选择排序冒泡排序插入排序归并排序

　　选择排序pub fn selection_sort(arr:&mut [T]) {     let len = arr.len();     for left in 0..len {         let mut smallest = left;         for right in (left+1)..len {             if arr[right] < arr[smallest] {                 smallest = right;             }         }         arr.swap(smallest, left);     } }  #[cfg(test)] mod tests {     use super::*;      #[test]     fn basic() {         let mut res = vec![＂f＂,＂d＂,＂e＂,＂a＂,＂c＂,＂b＂];         selection_sort(&mut res);         assert_eq!(res, vec![＂a＂,＂b＂,＂c＂,＂d＂,＂e＂,＂f＂]);     }     #[test]     fn empty() {         let mut res = Vec::::new();         selection_sort(&mut res);         assert_eq!(res, vec![]);     }      #[test]     fn one_element() {         let mut res = vec![＂a＂];         selection_sort(&mut res);         assert_eq!(res, vec![＂a＂]);     }      #[test]     fn pre_sorted() {         let mut res = vec![＂a＂,＂b＂,＂c＂,＂d＂];         selection_sort(&mut res);         assert_eq!(res, vec![＂a＂,＂b＂,＂c＂,＂d＂]);     } }冒泡排序 pub fn bubble_sort(arr:&mut [T]) {     if arr.is_empty() {         return;     }      let mut sorted = false;     let mut n = arr.len();     while!sorted {         sorted = true;         for i in 0..n-1{             if arr[i] > arr[i+1] {                 arr.swap(i,i+1);                 sorted = false;             }         }         n -= 1;     }  }  #[cfg(test)] mod tests {     use super::super::is_sorted;     use super::*;      #[test]     fn descending() {         let mut vec1 = vec![6,5,4,3,2,1];         bubble_sort(&mut vec1);         assert!(is_sorted(&vec1))     }      #[test]     fn ascending() {         let mut vec2 = vec![1,2,3,4,5];         bubble_sort(&mut vec2);         assert!(is_sorted(&vec2))     }      #[test]     fn empty() {         let mut vec3:Vec = vec![];         bubble_sort(&mut vec3);         assert!(is_sorted(&vec3))     } }插入排序 pub fn insertion_sort(arr:&mut [T]) where     T: PartialOrd+Copy {     for i in 1..arr.len() {         let cur = arr[i];         let mut j = i - 1;          while arr[j] > cur {             arr[j+1] = arr[j];             if j == 0 {                 break;             }             j -= 1;         }          // exit the loop from that break statement         if j == 0 && arr[0] > cur {             arr[0] = cur;         }else {             // `arr[j]>cur` is not satisfied ,exit from condition judgement             arr[j+1] =cur;         }     } }  #[cfg(test)] mod tests {     use super::super::is_sorted;     use super::*;      #[test]     fn empty() {         let mut arr:[u8;0] = [];         insertion_sort(&mut arr);         assert!(is_sorted(&arr));     }      #[test]     fn one_element() {         let mut arr:[char;1] = [＂a＂];         insertion_sort(&mut arr);         assert!(is_sorted(&arr));     }      #[test]     fn already_sorted() {         let mut arr:[&str;3] = [＂a＂,＂b＂,＂c＂];         insertion_sort(&mut arr);         assert!(is_sorted(&arr));     }      #[test]     fn basic() {         let mut arr:[&str;4] = [＂d＂,＂a＂,＂c＂,＂b＂];         insertion_sort(&mut arr);         assert!(is_sorted(&arr));     }      #[test]     fn repeated_elements() {         let mut arr: Vec = vec![542,542,542,542];         insertion_sort(&mut arr);         assert!(is_sorted(&arr));     } }归并排序fn merge(arr:&mut [T],mid:usize) {     // Create temporary vectors to support the merge     let left_half = arr[..mid].to_vec();     let right_half = arr[mid..].to_vec();      let mut l:usize = 0;     let mut r:usize = 0;      for v in arr {         if r == right_half.len() || (l < left_half.len() && left_half[l] < right_half[r]) {             *v = left_half[l];             l += 1;         }else {             *v = right_half[r];             r += 1;         }     }  }  pub fn top_down_merge_sort(arr:&mut [T]) {     if arr.len() > 1 {         let mid:usize = arr.len() / 2;         // Sort the left half recursively         top_down_merge_sort(&mut arr[..mid]);         // Sort the right half recursively         top_down_merge_sort(&mut arr[mid..]);         // Combine the two halves         merge(arr,mid)     } }  #[cfg(test)] mod tests {      #[cfg(test)]     mod top_down_merge_sort {         use super::super::*;          #[test]         fn basic() {             let mut res = vec![10,3,8,2,7,6,1,4,5,9];             top_down_merge_sort(&mut res);             assert_eq!(res, vec![1,2,3,4,5,6,7,8,9,10])         }          #[test]         fn basic_string() {             let mut res = vec![＂a＂,＂bb＂,＂d＂,＂cc＂];             top_down_merge_sort(&mut res);             assert_eq!(res,vec!(＂a＂,＂bb＂,＂cc＂,＂d＂))         }          #[test]         fn empty() {             let mut res = Vec::::new();             top_down_merge_sort(&mut res);             assert_eq!(res, vec![])         }          #[test]         fn one_element() {             let mut res = vec![1];             top_down_merge_sort(&mut res);             assert_eq!(res, vec![1])         }          #[test]         fn pre_sorted() {             let mut res = vec![1,2,3,4,5,6,7];             top_down_merge_sort(&mut res);             assert_eq!(res, vec![1,2,3,4,5,6,7])         }     } }