[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

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

zh-hant/codes/swift/chapter_sorting/merge_sort.swift

@@ -46,7 +46,7 @@ func mergeSort(nums: inout [Int], left: Int, right: Int) {
         return
     }
     // 劃分階段
-    let mid = (left + right) / 2 // 計算中點
+    let mid = left + (right - left) / 2 // 計算中點
     mergeSort(nums: &nums, left: left, right: mid) // 遞迴左子陣列
     mergeSort(nums: &nums, left: mid + 1, right: right) // 遞迴右子陣列
     // 合併階段

zh-hant/codes/swift/chapter_sorting/quick_sort.swift

@@ -54,7 +54,7 @@ func medianThree(nums: [Int], left: Int, mid: Int, right: Int) -> Int {
 /* 哨兵劃分（三數取中值） */
 func partitionMedian(nums: inout [Int], left: Int, right: Int) -> Int {
     // 選取三個候選元素的中位數
-    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)
     // 將中位數交換至陣列最左端
     nums.swapAt(left, med)
     return partition(nums: &nums, left: left, right: right)