aicodix___code/sort.hh
2024-03-08 11:01:38 +01:00

65 lines
1.2 KiB
C++

/*
Some stable sorting algorithms
Copyright 2024 Ahmet Inan <inan@aicodix.de>
*/
#pragma once
namespace CODE {
template <typename TYPE>
static void insertion_sort(TYPE *a, int n)
{
for (int i = 1, j; i < n; ++i) {
TYPE t = a[i];
for (j = i; j > 0 && a[j-1] > t; --j)
a[j] = a[j-1];
a[j] = t;
}
}
template <typename INDEX, typename TYPE>
static void insertion_sort(INDEX *p, TYPE *a, int n)
{
p[0] = 0;
for (int i = 1, j; i < n; ++i) {
TYPE t = a[i];
for (j = i; j > 0 && a[j-1] > t; --j) {
a[j] = a[j-1];
p[j] = p[j-1];
}
a[j] = t;
p[j] = i;
}
}
template <typename TYPE, int MAX_N, int M = 32>
class MergeSort
{
TYPE tmp[MAX_N];
void merge(TYPE *a, int n, int left, int right, int end)
{
if (right > n)
right = n;
if (end > n)
end = n;
for (int i = left, j = right, k = left; k < end; ++k)
tmp[k] = (i < right && (j >= end || a[i] <= a[j])) ? a[i++] : a[j++];
}
public:
void operator()(TYPE *a, int n)
{
for (int i = 0; i < n; i += M)
insertion_sort(a+i, i > n-M ? n-i : M);
for (int l = M; l < n; l *= 2) {
for (int i = 0; i < n; i += 2*l)
merge(a, n, i, i+l, i+2*l);
for (int i = 0; i < n; ++i)
a[i] = tmp[i];
}
}
};
}