{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "2167c041",
   "metadata": {},
   "source": [
    "# Troisième exercice Python (Niveau Lycée)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "bf9936e9",
   "metadata": {},
   "source": [
    "<img src=\"https://blog.univ-angers.fr/mathsinfo/files/2022/06/image-2.png\">"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "28f4e6cc",
   "metadata": {},
   "source": [
    "*Résumé en français* : un **isogram** (En français on parle d'**heterogramme**) est un mot qui ne contient aucune lettre répétée. Ecrire une fonction qui renvoie **vrai** ou **faux** suivant que le mot est un heterogramme, sans tenir compte de la casse (majuscule/minuscule)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "581b18f6",
   "metadata": {},
   "source": [
    "## Les ensembles"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "3bacce01",
   "metadata": {},
   "source": [
    "En JavaScript, on définit un ensemble de la façon suivante :"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "96eebc27",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Set(2) { 5, 1 }"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "new Set([5, 5, 1, 5, 1])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "19c6ec7a",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Set(5) { 'a', 'b', 'r', 'c', 'd' }"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "new Set('abracadabra')"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "c8e56dac",
   "metadata": {},
   "source": [
    "*L'idée principale* : On aura un heterogramme si la taille de l'ensemble des lettres utilisées pour écrire le mot est égal à la taille du mot initial. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "1b6e76f5",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[Function: isogram]"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "isogram = mot => mot.length == new Set(mot.toLowerCase()).size"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "3a4e580a",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "isogram('Dermatoglyphics')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "59601c48",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "false"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "isogram('aba')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "8a870e76",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "false"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "isogram('moOse')"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "9ce02163",
   "metadata": {},
   "source": [
    "Remarquez que le mot a besoin d'être mis en minuscule (ou majuscule) uniquement pour créer l'ensemble des lettres, pas pour trouver sa taille initiale. `len` permet en Python de donner la taille d'une chaine, d'une liste ou d'un dictionnaire."
   ]
  },
  {
   "cell_type": "markdown",
   "id": "2fb75793",
   "metadata": {},
   "source": [
    "## Recherche d'au moins une lettre en double"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "3d495a46",
   "metadata": {},
   "source": [
    "Une autre idée peut être de rechercher s'il existe au moins une lettre en double, par exemple en utilisant 2 boucles, en voici une version :"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "8a4ff2a6",
   "metadata": {},
   "outputs": [],
   "source": [
    "function isogram(mot) {\n",
    "  mot = mot.toLowerCase();\n",
    "  for (i = 0; i < mot.length - 1; i++) {\n",
    "    for (j = i + 1; j < mot.length; j++) {\n",
    "      if (mot[i] == mot[j]) return false;\n",
    "    }\n",
    "  }\n",
    "  return true;\n",
    "}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "b0e0c35b",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "isogram('Dermatoglyphics')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "id": "91414da7",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "false"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "isogram('aba')"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "5f75f965",
   "metadata": {},
   "source": [
    "## D'autres pistes..."
   ]
  },
  {
   "cell_type": "markdown",
   "id": "07b64b26",
   "metadata": {},
   "source": [
    "Ecrivons une **expression régulière** (Regex) qui va tester si une correspondance (`match` en anglais) existe entre un caractère (noté `.` en Regex) et ce même caractère un peu plus loin. "
   ]
  },
  {
   "cell_type": "markdown",
   "id": "093c031d",
   "metadata": {},
   "source": [
    "L'expression régulière est (exemple <a href=\"https://regex101.com/r/TjZRjh/1\" target=\"_blank\">ici avec le mot couleur</a>):\n",
    "\n",
    "<pre>(.).*\\1</pre>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "id": "04257b94",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[Function: isogram]"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "isogram = mot => !/(.).*\\1/i.test(mot.toLowerCase())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "id": "22660260",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "isogram('Dermatoglyphics')"
   ]
  }
 ],
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  "kernelspec": {
   "display_name": "JavaScript (Node.js)",
   "language": "javascript",
   "name": "javascript"
  },
  "language_info": {
   "file_extension": ".js",
   "mimetype": "application/javascript",
   "name": "javascript",
   "version": "18.3.0"
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 },
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