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Author: joeyajames

Sorting Algorithms/Radix_Sort.ipynb

@@ -0,0 +1,113 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Radix Sort\n",
+    "(c) 2020, Joe James"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# get number of digits in largest item\n",
+    "def __get_num_digits(A):\n",
+    "    m = 0\n",
+    "    for item in A:\n",
+    "        m = max(m, item)\n",
+    "    return len(str(m))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# flatten into a 1D List\n",
+    "from functools import reduce\n",
+    "def __flatten(A):\n",
+    "    return reduce(lambda x, y: x + y, A)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def radix(A, num_digits):\n",
+    "    for digit in range(0, num_digits):\n",
+    "        B = [[] for i in range(10)]\n",
+    "        for item in A:\n",
+    "            # num is the bucket number that the item will be put into\n",
+    "            num = item // 10 ** (digit) % 10\n",
+    "            B[num].append(item)\n",
+    "        A = __flatten(B)\n",
+    "    return A"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[1, 2, 3, 45, 53, 55, 213, 288, 289]\n",
+      "[0, 1, 2, 3, 4, 5] [999994, 999995, 999996, 999997, 999998, 999999]\n"
+     ]
+    }
+   ],
+   "source": [
+    "def main():\n",
+    "    A = [55, 45, 3, 289, 213, 1, 288, 53, 2]\n",
+    "    num_digits = __get_num_digits(A)\n",
+    "    A = radix(A, num_digits)\n",
+    "    print(A)\n",
+    "    \n",
+    "    B  = [i for i in range(1000000)]\n",
+    "    from random import shuffle\n",
+    "    shuffle(B)\n",
+    "    B = radix(B, __get_num_digits(B))\n",
+    "    print(B[:6], B[-6:])\n",
+    "\n",
+    "main()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "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": "3.7.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}