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{"nbformat_minor": 0, "cells": [{"source": "#Chapter 03: Algorithms", "cell_type": "markdown", "metadata": {}}, {"source": "## Example 03: Page 195", "cell_type": "markdown", "metadata": {}}, {"execution_count": 1, "cell_type": "code", "source": "def binarysearch(a,num): #function definition with its parameters 'a' is the inputlist\n #and 'num' number to be found\n\n first=0 #initially the first position is zero\n last=len(a)-1 #initially the last position is the total length of the inputlist-1\n found=False #boolean value to indicate if the number to be searched is found or not.\n\n while first<=last and not found:\n midpoint=(first+last)//2 #dividing the inputlist into two halves and comparing the number to be found with the midpoint.\n\n if a[midpoint]==num: #If the number to be found is equal to the midpoint returns the position.\n found=True\n else:\n if num<a[midpoint]: #if the number to be found is less than the midpoint\n #then the first half of the divided input list is taken for further computation.\n\n last=midpoint-1 #by assigning the last number of the first half(number before the midpoint) to the variable last.\n\n\n else:\n first=midpoint+1 #if the number to be found is greater than the midpoint\n #then the second half of the divided input list is taken for further computation.\n #by assigning the first number of the second half(number following the midpoint) to the variable first.\n\n return midpoint #returns the position of the number found in the list. \n\n\n\nnumlist=[1, 23, 5, 6, 7, 8, 10, 12, 13, 15, 16, 18, 19, 20, 22] #List of inputs\nprint \"Found number 19 at the position\",(binarysearch(numlist, 19)) #Printing the position of the number to be found by a function call.\n #The function binarysearch is called along with its parameters, inputlist\n #and the number to be found.\n\n\n", "outputs": [{"output_type": "stream", "name": "stdout", "text": "Found number 19 at the position 12\n"}], "metadata": {"collapsed": false, "trusted": true}}, {"source": "##Example 05: Page 198", "cell_type": "markdown", "metadata": {}}, {"execution_count": 2, "cell_type": "code", "source": "#To perform insertionsort\ndef sort_insertion(inputlist):\n\n for i in range(1,len(inputlist)):\n\n val_current = inputlist[i]\n pos = i \n \n # check backwards through sorted list for proper pos of val_current\n while((pos > 0) and (inputlist[pos-1] > val_current)):\n inputlist[pos] = inputlist[pos-1]\n pos = pos-1\n \n if pos != i:\n inputlist[pos] = val_current \n print(inputlist)\n return inputlist\ninputlist = [3,2,4,1,5]\nprint sort_insertion(inputlist)\n", "outputs": [{"output_type": "stream", "name": "stdout", "text": "[2, 3, 4, 1, 5]\n[1, 2, 3, 4, 5]\n[1, 2, 3, 4, 5]\n"}], "metadata": {"collapsed": false, "trusted": true}}, {"source": "", "cell_type": "markdown", "metadata": {}}, {"source": "", "cell_type": "markdown", "metadata": {}}], "nbformat": 4, "metadata": {"kernelspec": {"display_name": "Python 2", "name": "python2", "language": "python"}, "language_info": {"mimetype": "text/x-python", "nbconvert_exporter": "python", "version": "2.7.9", "name": "python", "file_extension": ".py", "pygments_lexer": "ipython2", "codemirror_mode": {"version": 2, "name": "ipython"}}}}
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