From cf60e38b9db07933578e9c76b088284ad2c5281e Mon Sep 17 00:00:00 2001
From: Ahmet Inan <inan@aicodix.de>
Date: Mon, 11 Mar 2024 10:42:28 +0100
Subject: [PATCH] we ain't come this far to omit sorting

---
 quick_select.hh => quick.hh | 19 ++++++++++++++++++-
 repeated_median.hh          |  2 +-
 tests/quick_select_test.cc  |  2 +-
 tests/quick_sort_test.cc    | 36 ++++++++++++++++++++++++++++++++++++
 theil_sen.hh                |  2 +-
 5 files changed, 57 insertions(+), 4 deletions(-)
 rename quick_select.hh => quick.hh (81%)
 create mode 100644 tests/quick_sort_test.cc

diff --git a/quick_select.hh b/quick.hh
similarity index 81%
rename from quick_select.hh
rename to quick.hh
index e27a5f0..568a4fe 100644
--- a/quick_select.hh
+++ b/quick.hh
@@ -1,5 +1,5 @@
 /*
-Quick select algorithm
+Quick algorithms for sorting and selecting
 
 Copyright 2024 Ahmet Inan <inan@aicodix.de>
 */
@@ -57,6 +57,17 @@ static void partition(TYPE *a, int &l, int &h)
 			++i;
 }
 
+template <typename TYPE>
+static void sort(TYPE *a, int l, int h)
+{
+	if (l < h) {
+		int lt = l, gt = h;
+		partition(a, lt, gt);
+		sort(a, l, lt - 1);
+		sort(a, gt + 1, h);
+	}
+}
+
 template <typename TYPE>
 static void select(TYPE *a, int l, int h, int k)
 {
@@ -74,6 +85,12 @@ static void select(TYPE *a, int l, int h, int k)
 
 }
 
+template <typename TYPE>
+void quick_sort(TYPE *a, int n)
+{
+	QUICK::sort(a, 0, n-1);
+}
+
 template <typename TYPE>
 TYPE quick_select(TYPE *a, int k, int n)
 {
diff --git a/repeated_median.hh b/repeated_median.hh
index 6e8944c..4a8612f 100644
--- a/repeated_median.hh
+++ b/repeated_median.hh
@@ -6,7 +6,7 @@ Copyright 2021 Ahmet Inan <inan@aicodix.de>
 
 #pragma once
 
-#include "quick_select.hh"
+#include "quick.hh"
 
 namespace DSP {
 
diff --git a/tests/quick_select_test.cc b/tests/quick_select_test.cc
index 15795f7..aafaa62 100644
--- a/tests/quick_select_test.cc
+++ b/tests/quick_select_test.cc
@@ -8,7 +8,7 @@ Copyright 2024 Ahmet Inan <inan@aicodix.de>
 #include <cassert>
 #include <iostream>
 #include <functional>
-#include "quick_select.hh"
+#include "quick.hh"
 
 int main()
 {
diff --git a/tests/quick_sort_test.cc b/tests/quick_sort_test.cc
new file mode 100644
index 0000000..6e1f93d
--- /dev/null
+++ b/tests/quick_sort_test.cc
@@ -0,0 +1,36 @@
+/*
+Test for the Quick sort algorithm
+
+Copyright 2024 Ahmet Inan <inan@aicodix.de>
+*/
+
+#include <random>
+#include <cassert>
+#include <iostream>
+#include <functional>
+#include "quick.hh"
+
+int main()
+{
+	const int MAX_N = 1 << 16;
+	unsigned seed = 42;
+	if (1) {
+		std::random_device rd;
+		seed = rd();
+	}
+	typedef std::default_random_engine generator;
+	typedef std::uniform_int_distribution<int> distribution;
+	auto rand = std::bind(distribution(0, MAX_N), generator(seed));
+	int a[MAX_N];
+	for (int loop = 0; loop < 1000; ++loop) {
+		int size = rand();
+		for (int i = 0; i < size; ++i)
+			a[i] = rand();
+		DSP::quick_sort(a, size);
+		for (int i = 1; i < size; ++i)
+			assert(a[i-1] <= a[i]);
+	}
+	std::cerr << "Quick sort algorithm test passed!" << std::endl;
+	return 0;
+}
+
diff --git a/theil_sen.hh b/theil_sen.hh
index 5b6055f..4b17f82 100644
--- a/theil_sen.hh
+++ b/theil_sen.hh
@@ -6,7 +6,7 @@ Copyright 2021 Ahmet Inan <inan@aicodix.de>
 
 #pragma once
 
-#include "quick_select.hh"
+#include "quick.hh"
 
 namespace DSP {