we ain't come this far to omit sorting

This commit is contained in:
Ahmet Inan 2024-03-11 10:42:28 +01:00
commit cf60e38b9d
5 changed files with 57 additions and 4 deletions

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@ -1,5 +1,5 @@
/* /*
Quick select algorithm Quick algorithms for sorting and selecting
Copyright 2024 Ahmet Inan <inan@aicodix.de> Copyright 2024 Ahmet Inan <inan@aicodix.de>
*/ */
@ -57,6 +57,17 @@ static void partition(TYPE *a, int &l, int &h)
++i; ++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> template <typename TYPE>
static void select(TYPE *a, int l, int h, int k) 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> template <typename TYPE>
TYPE quick_select(TYPE *a, int k, int n) TYPE quick_select(TYPE *a, int k, int n)
{ {

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@ -6,7 +6,7 @@ Copyright 2021 Ahmet Inan <inan@aicodix.de>
#pragma once #pragma once
#include "quick_select.hh" #include "quick.hh"
namespace DSP { namespace DSP {

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@ -8,7 +8,7 @@ Copyright 2024 Ahmet Inan <inan@aicodix.de>
#include <cassert> #include <cassert>
#include <iostream> #include <iostream>
#include <functional> #include <functional>
#include "quick_select.hh" #include "quick.hh"
int main() int main()
{ {

36
tests/quick_sort_test.cc Normal file
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@ -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;
}

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@ -6,7 +6,7 @@ Copyright 2021 Ahmet Inan <inan@aicodix.de>
#pragma once #pragma once
#include "quick_select.hh" #include "quick.hh"
namespace DSP { namespace DSP {