Skip to content

Commit

Permalink
added initial versions of countingsort and radixsort
Browse files Browse the repository at this point in the history
  • Loading branch information
@JensLiebehenschel
JensLiebehenschel committed Apr 3, 2021
1 parent f65fddc commit 72cf9d1
Show file tree
Hide file tree
Showing 2 changed files with 721 additions and 0 deletions.
316 changes: 316 additions & 0 deletions Countingsort/Countingsort.ipynb
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,316 @@
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Copyright 2021 Jens Liebehenschel, Frankfurt University of Applied Sciences, FB2, Computer Science\n",
"### No liability or warranty; only for educational and non-commercial purposes\n",
"### See some basic hints for working with Jupyter notebooks in README.md\n",
"## Sorting an array using countingsort"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {},
"outputs": [],
"source": [
"def countingsort(A):\n",
" # create temporary array C for counting\n",
" C=[0 for x in range(max(A)+1)]\n",
" print_array_C(C)\n",
"\n",
" # count number of elements = i in C[i]\n",
" for j in range(len(A)):\n",
" C[A[j]] = C[A[j]] + 1\n",
" print_array_C(C)\n",
" \n",
" # calculate number of elements <= i in C[i]\n",
" for i in range(1,len(C)):\n",
" C[i] = C[i] + C[i-1]\n",
" print_array_C(C)\n",
"\n",
" # create (empty) output array B\n",
" B=[-1 for x in range(len(A))]\n",
"\n",
" # create sorted output\n",
" for j in range(len(A)-1,-1,-1):\n",
" B[C[A[j]]-1] = A[j]\n",
" C[A[j]] = C[A[j]] - 1\n",
" print_array_C(C)\n",
" \n",
" return B"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"outputs": [],
"source": [
"# checks whether array is sorted correctly, this also works with identical keys in the array\n",
"def check_sorting(a):\n",
" return all(a[i] <= a[i+1] for i in range(len(a)-1))"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {},
"outputs": [],
"source": [
"def print_array_C(C):\n",
" if output_temp_array:\n",
" print (\"C:\",C)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Constants"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {},
"outputs": [],
"source": [
"# The size of elements in tests can be changed here\n",
"ARRAY_SIZE = 10\n",
"# Some output text\n",
"TEXT_BEFORE_SORTING = \"Before sorting:\"\n",
"TEXT_AFTER_SORTING = \"After sorting:\"\n",
"TEXT_CHECK_SORTING = \"Sorting correct? -\""
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Configuration of output "
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {},
"outputs": [],
"source": [
"# change output settings here\n",
"output_temp_array = False\n",
"output_temp_array = True"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Generate test data and test algorithm"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Before sorting: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n",
"C: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]\n",
"C: [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]\n",
"C: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]\n",
"C: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n",
"After sorting: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n",
"Sorting correct? - True\n"
]
}
],
"source": [
"# test sorting sorted array\n",
"sorted_array = list(range(ARRAY_SIZE))\n",
"print(TEXT_BEFORE_SORTING, sorted_array)\n",
"a = countingsort(sorted_array)\n",
"print(TEXT_AFTER_SORTING, a)\n",
"print(TEXT_CHECK_SORTING, check_sorting(a))"
]
},
{
"cell_type": "code",
"execution_count": 7,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Before sorting: [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]\n",
"C: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]\n",
"C: [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]\n",
"C: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]\n",
"C: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n",
"After sorting: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n",
"Sorting correct? - True\n"
]
}
],
"source": [
"# test sorting reversly sorted array\n",
"reverse_sorted_array = list(range(ARRAY_SIZE-1, -1, -1))\n",
"print(TEXT_BEFORE_SORTING, reverse_sorted_array)\n",
"a = countingsort(reverse_sorted_array)\n",
"print(TEXT_AFTER_SORTING, a)\n",
"print(TEXT_CHECK_SORTING, check_sorting(a))"
]
},
{
"cell_type": "code",
"execution_count": 8,
"metadata": {
"scrolled": true
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Before sorting: [2, 8, 4, 9, 1, 6, 7, 3, 0, 5]\n",
"C: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]\n",
"C: [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]\n",
"C: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]\n",
"C: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n",
"After sorting: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n",
"Sorting correct? - True\n"
]
}
],
"source": [
"# test sorting random array\n",
"# use numpy for generating a permutation\n",
"import numpy\n",
"# initialialize random number generator to obtain reproducable results\n",
"# other values might be used or even no initialization done here\n",
"numpy.random.seed(0)\n",
"# now generate random data and test sorting\n",
"array = list(numpy.random.permutation(ARRAY_SIZE))\n",
"print(TEXT_BEFORE_SORTING, array)\n",
"a = countingsort(array)\n",
"print(TEXT_AFTER_SORTING, a)\n",
"print(TEXT_CHECK_SORTING, check_sorting(a))"
]
},
{
"cell_type": "code",
"execution_count": 9,
"metadata": {},
"outputs": [],
"source": [
"output_temp_array_last_state = output_temp_array\n",
"output_temp_array = False"
]
},
{
"cell_type": "code",
"execution_count": 10,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Before sorting: [36, 87, 70, 88, 140, 58, 193, 39, 87, 174, 88, 81, 165, 25, 77, 72, 9, 148, 115, 197]\n",
"After sorting: [9, 25, 36, 39, 58, 70, 72, 77, 81, 87, 87, 88, 88, 115, 140, 148, 165, 174, 193, 197]\n",
"Sorting correct? - True\n"
]
}
],
"source": [
"# now generate random data and test sorting\n",
"MAX_VALUE = 200\n",
"ARRAY_SIZE = 20\n",
"array = [numpy.random.randint(MAX_VALUE) for x in range(ARRAY_SIZE)]\n",
"print(TEXT_BEFORE_SORTING, array)\n",
"a = countingsort(array)\n",
"print(TEXT_AFTER_SORTING, a)\n",
"print(TEXT_CHECK_SORTING, check_sorting(a))"
]
},
{
"cell_type": "code",
"execution_count": 11,
"metadata": {},
"outputs": [],
"source": [
"output_temp_array = output_temp_array_last_state"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### your tests here ..."
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Before sorting: [1, 3, 2]\n",
"C: [0, 0, 0, 0]\n",
"C: [0, 1, 1, 1]\n",
"C: [0, 1, 2, 3]\n",
"C: [0, 0, 1, 2]\n",
"After sorting: [1, 2, 3]\n",
"Sorting correct? - True\n"
]
}
],
"source": [
"array = [1,3,2]\n",
"print(TEXT_BEFORE_SORTING, array)\n",
"a = countingsort(array)\n",
"print(TEXT_AFTER_SORTING, a)\n",
"print(TEXT_CHECK_SORTING, check_sorting(a))"
]
},
{
"cell_type": "code",
"execution_count": 13,
"metadata": {},
"outputs": [],
"source": [
"# ... and here ..."
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.8.5"
}
},
"nbformat": 4,
"nbformat_minor": 4
}

0 comments on commit 72cf9d1

Please sign in to comment.