f97b3a2391
Moved __get_num_digits() function call into the radix() function, so the only parameter when calling radix() is a List.
122 lines
2.7 KiB
Plaintext
122 lines
2.7 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Radix Sort\n",
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"(c) 2020, Joe James"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {},
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"outputs": [],
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"source": [
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"# get number of digits in largest item\n",
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"def __get_num_digits(A):\n",
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" m = 0\n",
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" for item in A:\n",
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" m = max(m, item)\n",
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" return len(str(m))"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 2,
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"metadata": {},
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"outputs": [],
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"source": [
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"# flatten into a 1D List\n",
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"from functools import reduce\n",
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"def __flatten(A):\n",
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" return reduce(lambda x, y: x + y, A)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"### Changed from YouTube video:\n",
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"It's much cleaner to put the _get_num_digits call inside the radix function rather than in main as shown in the video. That way you only need to pass a List to the radix function. Thanks to Brother Lui for this suggestion."
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]
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},
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{
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"cell_type": "code",
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"execution_count": 3,
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"metadata": {},
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"outputs": [],
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"source": [
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"def radix(A):\n",
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" num_digits = __get_num_digits(A)\n",
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" for digit in range(0, num_digits):\n",
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" B = [[] for i in range(10)]\n",
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" for item in A:\n",
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" # num is the bucket number that the item will be put into\n",
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" num = item // 10 ** (digit) % 10\n",
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" B[num].append(item)\n",
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" A = __flatten(B)\n",
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" return A"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 4,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"[1, 2, 3, 45, 53, 55, 213, 288, 289]\n",
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"[0, 1, 2, 3, 4, 5] [999994, 999995, 999996, 999997, 999998, 999999]\n"
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]
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}
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],
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"source": [
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"def main():\n",
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" A = [55, 45, 3, 289, 213, 1, 288, 53, 2]\n",
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" A = radix(A)\n",
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" print(A)\n",
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" \n",
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" B = [i for i in range(1000000)]\n",
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" from random import shuffle\n",
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" shuffle(B)\n",
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" B = radix(B)\n",
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" print(B[:6], B[-6:])\n",
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"\n",
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"main()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": []
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.7.0"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 2
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}
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