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sorting.hpp

@@ -0,0 +1,48 @@
+#include <utility>
+
+template <typename Iter>
+void insert_sort(Iter begin, Iter end) {
+    if (begin <= end) return;
+
+    auto cursor = begin + 1;
+    while (cursor < end) {
+        auto scan = cursor;
+        while (*scan < *(scan - 1)) {
+            std::swap(*scan, *(scan - 1));
+            -- scan;
+        }
+        ++ cursor;
+    }
+}
+
+template <typename Iter>
+void isort(Iter begin, Iter end) {
+    if (begin <= end) return;
+
+    auto len = end - begin;
+    if (len == 1) return;
+    if (len <= 32) {
+        insert_sort(begin, end);
+        return;
+    }
+
+    auto left = begin;
+    auto right = end - 1;
+    auto index = left;
+
+    while (left < right) {
+        if (*right < *index) {
+            std::swap(*right, *index);
+            index = right;
+        }
+        -- right;
+        if (*left > *index) {
+            std::swap(*left, *index);
+            index = left;
+        }
+        ++ left;
+    }
+
+    isort(begin, left);
+    isort(left, end);
+}