From 4144ab422eb89431f0c9ffaed8e1e4b47d062043 Mon Sep 17 00:00:00 2001
From: robtor <robtor2000@web.de>
Date: Tue, 5 Dec 2023 10:54:45 +0100
Subject: [PATCH] Revert "Remove unnecessary copy"

This reverts commit e732d062b6efc6bf5d6ffccab3b4261ae34eaf57.
---
 task2/include/quicksort_mt.h | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/task2/include/quicksort_mt.h b/task2/include/quicksort_mt.h
index 506f654..6d57e78 100644
--- a/task2/include/quicksort_mt.h
+++ b/task2/include/quicksort_mt.h
@@ -20,11 +20,13 @@ public:
 private:
     auto parition(std::span<T> &data) -> std::pair<std::span<T>, std::span<T>> {
 
-        auto pivot = data.begin();
-        std::advance(pivot, std::distance(data.begin(), data.end()) / 2);
+        std::vector<T> buf(data);
 
-        auto lefti = data.begin();
-        auto righti = data.end();
+        auto pivot = buf.begin();
+        std::advance(pivot, std::distance(buf.begin(), buf.end()) / 2);
+
+        auto lefti = buf.begin();
+        auto righti = buf.end();
 
         while (1) {
             for (; cmp(*lefti, *pivot); lefti++);
@@ -37,6 +39,7 @@ private:
             std::swap(lefti, righti);
         }
 
+        std::move(buf.begin(), buf.end(), data.begin());
         return {std::span<T>(data.begin(), lefti), std::span<T>(lefti, data.end())};
     }