[Rust] Normalize mid calculation in case overflow (#1363)

* Normalize mid calculate in case overflow

* Change ALL language

* Update merge_sort.py

* Update merge_sort.zig

* Update binary_search_tree.zig

* Update binary_search_recur.py

---------

Co-authored-by: Yudong Jin <krahets@163.com>

codes/c/chapter_sorting/merge_sort.c

@@ -43,7 +43,7 @@ void mergeSort(int *nums, int left, int right) {
     if (left >= right)
         return; // 当子数组长度为 1 时终止递归
     // 划分阶段
-    int mid = (left + right) / 2;    // 计算中点
+    int mid = left + (right - left) / 2;    // 计算中点
     mergeSort(nums, left, mid);      // 递归左子数组
     mergeSort(nums, mid + 1, right); // 递归右子数组
     // 合并阶段

codes/cpp/chapter_sorting/merge_sort.cpp

@@ -39,7 +39,7 @@ void mergeSort(vector<int> &nums, int left, int right) {
     if (left >= right)
         return; // 当子数组长度为 1 时终止递归
     // 划分阶段
-    int mid = (left + right) / 2;    // 计算中点
+    int mid = left + (right - left) / 2;    // 计算中点
     mergeSort(nums, left, mid);      // 递归左子数组
     mergeSort(nums, mid + 1, right); // 递归右子数组
     // 合并阶段

codes/csharp/chapter_sorting/merge_sort.cs

@@ -39,7 +39,7 @@ public class merge_sort {
         // 终止条件
         if (left >= right) return;       // 当子数组长度为 1 时终止递归
         // 划分阶段
-        int mid = (left + right) / 2;    // 计算中点
+        int mid = left + (right - left) / 2;    // 计算中点
         MergeSort(nums, left, mid);      // 递归左子数组
         MergeSort(nums, mid + 1, right); // 递归右子数组
         // 合并阶段

codes/dart/chapter_sorting/merge_sort.dart

@@ -36,7 +36,7 @@ void mergeSort(List<int> nums, int left, int right) {
   // 终止条件
   if (left >= right) return; // 当子数组长度为 1 时终止递归
   // 划分阶段
-  int mid = (left + right) ~/ 2; // 计算中点
+  int mid = left + (right - left) ~/ 2; // 计算中点
   mergeSort(nums, left, mid); // 递归左子数组
   mergeSort(nums, mid + 1, right); // 递归右子数组
   // 合并阶段

codes/go/chapter_sorting/merge_sort.go

@@ -46,7 +46,7 @@ func mergeSort(nums []int, left, right int) {
 		return
 	}
 	// 划分阶段
-	mid := (left + right) / 2
+	mid := left + (right - left) / 2
 	mergeSort(nums, left, mid)
 	mergeSort(nums, mid+1, right)
 	// 合并阶段

codes/java/chapter_sorting/merge_sort.java

@@ -42,7 +42,7 @@ public class merge_sort {
         if (left >= right)
             return; // 当子数组长度为 1 时终止递归
         // 划分阶段
-        int mid = (left + right) / 2; // 计算中点
+        int mid = left + (right - left) / 2; // 计算中点
         mergeSort(nums, left, mid); // 递归左子数组
         mergeSort(nums, mid + 1, right); // 递归右子数组
         // 合并阶段

codes/javascript/chapter_sorting/merge_sort.js

@@ -39,7 +39,7 @@ function mergeSort(nums, left, right) {
     // 终止条件
     if (left >= right) return; // 当子数组长度为 1 时终止递归
     // 划分阶段
-    let mid = Math.floor((left + right) / 2); // 计算中点
+    let mid = Math.floor(left + (right - left) / 2); // 计算中点
     mergeSort(nums, left, mid); // 递归左子数组
     mergeSort(nums, mid + 1, right); // 递归右子数组
     // 合并阶段

codes/kotlin/chapter_sorting/merge_sort.kt

@@ -40,7 +40,7 @@ fun mergeSort(nums: IntArray, left: Int, right: Int) {
     // 终止条件
     if (left >= right) return  // 当子数组长度为 1 时终止递归
     // 划分阶段
-    val mid = (left + right) / 2 // 计算中点
+    val mid = left + (right - left) / 2 // 计算中点
     mergeSort(nums, left, mid) // 递归左子数组
     mergeSort(nums, mid + 1, right) // 递归右子数组
     // 合并阶段
@@ -53,4 +53,4 @@ fun main() {
     val nums = intArrayOf(7, 3, 2, 6, 0, 1, 5, 4)
     mergeSort(nums, 0, nums.size - 1)
     println("归并排序完成后 nums = ${nums.contentToString()}")
-}
+}

codes/python/chapter_sorting/merge_sort.py

@@ -41,7 +41,7 @@ def merge_sort(nums: list[int], left: int, right: int):
     if left >= right:
         return  # 当子数组长度为 1 时终止递归
     # 划分阶段
-    mid = (left + right) // 2  # 计算中点
+    mid = (left + right) // 2 # 计算中点
     merge_sort(nums, left, mid)  # 递归左子数组
     merge_sort(nums, mid + 1, right)  # 递归右子数组
     # 合并阶段

codes/ruby/chapter_sorting/merge_sort.rb

@@ -45,7 +45,7 @@ def merge_sort(nums, left, right)
   # 当子数组长度为 1 时终止递归
   return if left >= right
   # 划分阶段
-  mid = (left + right) / 2 # 计算中点
+  mid = left + (right - left) / 2 # 计算中点
   merge_sort(nums, left, mid) # 递归左子数组
   merge_sort(nums, mid + 1, right) # 递归右子数组
   # 合并阶段

codes/rust/chapter_divide_and_conquer/binary_search_recur.rs

@@ -10,7 +10,7 @@ fn dfs(nums: &[i32], target: i32, i: i32, j: i32) -> i32 {
     if i > j {
         return -1;
     }
-    let m: i32 = (i + j) / 2;
+    let m: i32 = i + (j - i) / 2;
     if nums[m as usize] < target {
         // 递归子问题 f(m+1, j)
         return dfs(nums, target, m + 1, j);

codes/rust/chapter_sorting/merge_sort.rs

@@ -48,7 +48,7 @@ fn merge_sort(nums: &mut [i32], left: usize, right: usize) {
     }
 
     // 划分阶段
-    let mid = (left + right) / 2; // 计算中点
+    let mid = left + (right - left) / 2; // 计算中点
     merge_sort(nums, left, mid); // 递归左子数组
     merge_sort(nums, mid + 1, right); // 递归右子数组
 

codes/rust/chapter_sorting/radix_sort.rs

@@ -35,9 +35,7 @@ fn counting_sort_digit(nums: &mut [i32], exp: i32) {
         counter[d] -= 1; // 将 d 的数量减 1
     }
     // 使用结果覆盖原数组 nums
-    for i in 0..n {
-        nums[i] = res[i];
-    }
+    nums.copy_from_slice(&res);
 }
 
 /* 基数排序 */

codes/swift/chapter_sorting/merge_sort.swift

@@ -46,7 +46,7 @@ func mergeSort(nums: inout [Int], left: Int, right: Int) {
         return
     }
     // 划分阶段
-    let mid = (left + right) / 2 // 计算中点
+    let mid = left + (right - left) / 2 // 计算中点
     mergeSort(nums: &nums, left: left, right: mid) // 递归左子数组
     mergeSort(nums: &nums, left: mid + 1, right: right) // 递归右子数组
     // 合并阶段

codes/swift/chapter_sorting/quick_sort.swift

@@ -54,7 +54,7 @@ func medianThree(nums: [Int], left: Int, mid: Int, right: Int) -> Int {
 /* 哨兵划分（三数取中值） */
 func partitionMedian(nums: inout [Int], left: Int, right: Int) -> Int {
     // 选取三个候选元素的中位数
-    let med = medianThree(nums: nums, left: left, mid: (left + right) / 2, right: right)
+    let med = medianThree(nums: nums, left: left, mid: left + (right - left) / 2, right: right)
     // 将中位数交换至数组最左端
     nums.swapAt(left, med)
     return partition(nums: &nums, left: left, right: right)

codes/typescript/chapter_sorting/merge_sort.ts

@@ -39,7 +39,7 @@ function mergeSort(nums: number[], left: number, right: number): void {
     // 终止条件
     if (left >= right) return; // 当子数组长度为 1 时终止递归
     // 划分阶段
-    let mid = Math.floor((left + right) / 2); // 计算中点
+    let mid = Math.floor(left + (right - left) / 2); // 计算中点
     mergeSort(nums, left, mid); // 递归左子数组
     mergeSort(nums, mid + 1, right); // 递归右子数组
     // 合并阶段

codes/zig/chapter_sorting/merge_sort.zig

@@ -15,10 +15,10 @@ fn merge(nums: []i32, left: usize, mid: usize, right: usize) !void {
     const mem_allocator = mem_arena.allocator();
     var tmp = try mem_allocator.alloc(i32, right + 1 - left);
     std.mem.copy(i32, tmp, nums[left..right+1]);
-    // 左子数组的起始索引和结束索引  
+    // 左子数组的起始索引和结束索引
     var leftStart = left - left;
     var leftEnd = mid - left;
-    // 右子数组的起始索引和结束索引       
+    // 右子数组的起始索引和结束索引
     var rightStart = mid + 1 - left;
     var rightEnd = right - left;
     // i, j 分别指向左子数组、右子数组的首元素
@@ -48,7 +48,7 @@ fn mergeSort(nums: []i32, left: usize, right: usize) !void {
     // 终止条件
     if (left >= right) return;              // 当子数组长度为 1 时终止递归
     // 划分阶段
-    var mid = (left + right) / 2;           // 计算中点
+    var mid = left + (right - left) / 2;    // 计算中点
     try mergeSort(nums, left, mid);         // 递归左子数组
     try mergeSort(nums, mid + 1, right);    // 递归右子数组
     // 合并阶段
@@ -64,4 +64,4 @@ pub fn main() !void {
     inc.PrintUtil.printArray(i32, &nums);
 
     _ = try std.io.getStdIn().reader().readByte();
-}
+}

codes/zig/chapter_tree/binary_search_tree.zig

@@ -34,7 +34,7 @@ pub fn BinarySearchTree(comptime T: type) type {
         fn buildTree(self: *Self, nums: []T, i: usize, j: usize) !?*inc.TreeNode(T) {
             if (i > j) return null;
             // 将数组中间节点作为根节点
-            var mid = (i + j) / 2;
+            var mid = i + (j - i) / 2;
             var node = try self.mem_allocator.create(inc.TreeNode(T));
             node.init(nums[mid]);
             // 递归建立左子树和右子树
@@ -145,7 +145,7 @@ pub fn BinarySearchTree(comptime T: type) type {
                 cur.?.val = tmp_val;
             }
         }
-    };   
+    };
 }
 
 // Driver Code
@@ -179,4 +179,4 @@ pub fn main() !void {
     try inc.PrintUtil.printTree(bst.getRoot(), null, false);
 
     _ = try std.io.getStdIn().reader().readByte();
-}
+}