euler38.ipynb

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  10     {
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  13        "true"
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  16      "execution_count": 1,
  17      "metadata": {},
  18      "output_type": "execute_result"
  19     }
  20    ],
  21    "source": [
  22     "load 'array-numbers.rb'"
  23    ]
  24   },
  25   {
  26    "cell_type": "code",
  27    "execution_count": 15,
  28    "metadata": {
  29     "collapsed": false
  30    },
  31    "outputs": [
  32     {
  33      "data": {
  34       "text/plain": [
  35        ":pandigital?"
  36       ]
  37      },
  38      "execution_count": 15,
  39      "metadata": {},
  40      "output_type": "execute_result"
  41     }
  42    ],
  43    "source": [
  44     "class Integer\n",
  45     "  def pandigital?(start=1)\n",
  46     "    self.to_digits.sort == (start..9).to_a\n",
  47     "  end\n",
  48     "end"
  49    ]
  50   },
  51   {
  52    "cell_type": "code",
  53    "execution_count": 16,
  54    "metadata": {
  55     "collapsed": false
  56    },
  57    "outputs": [
  58     {
  59      "data": {
  60       "text/plain": [
  61        "true"
  62       ]
  63      },
  64      "execution_count": 16,
  65      "metadata": {},
  66      "output_type": "execute_result"
  67     }
  68    ],
  69    "source": [
  70     "192384576.pandigital?"
  71    ]
  72   },
  73   {
  74    "cell_type": "code",
  75    "execution_count": 17,
  76    "metadata": {
  77     "collapsed": false
  78    },
  79    "outputs": [
  80     {
  81      "data": {
  82       "text/plain": [
  83        "false"
  84       ]
  85      },
  86      "execution_count": 17,
  87      "metadata": {},
  88      "output_type": "execute_result"
  89     }
  90    ],
  91    "source": [
  92     "343553.pandigital?"
  93    ]
  94   },
  95   {
  96    "cell_type": "code",
  97    "execution_count": 18,
  98    "metadata": {
  99     "collapsed": false
 100    },
 101    "outputs": [
 102     {
 103      "data": {
 104       "text/plain": [
 105        "false"
 106       ]
 107      },
 108      "execution_count": 18,
 109      "metadata": {},
 110      "output_type": "execute_result"
 111     }
 112    ],
 113    "source": [
 114     "19238457.pandigital?"
 115    ]
 116   },
 117   {
 118    "cell_type": "code",
 119    "execution_count": 19,
 120    "metadata": {
 121     "collapsed": false
 122    },
 123    "outputs": [
 124     {
 125      "data": {
 126       "text/plain": [
 127        "false"
 128       ]
 129      },
 130      "execution_count": 19,
 131      "metadata": {},
 132      "output_type": "execute_result"
 133     }
 134    ],
 135    "source": [
 136     "1923845706.pandigital?"
 137    ]
 138   },
 139   {
 140    "cell_type": "code",
 141    "execution_count": 20,
 142    "metadata": {
 143     "collapsed": false
 144    },
 145    "outputs": [
 146     {
 147      "data": {
 148       "text/plain": [
 149        "true"
 150       ]
 151      },
 152      "execution_count": 20,
 153      "metadata": {},
 154      "output_type": "execute_result"
 155     }
 156    ],
 157    "source": [
 158     "1923845706.pandigital?(0)"
 159    ]
 160   },
 161   {
 162    "cell_type": "code",
 163    "execution_count": 25,
 164    "metadata": {
 165     "collapsed": false
 166    },
 167    "outputs": [
 168     {
 169      "data": {
 170       "text/plain": [
 171        "[2]"
 172       ]
 173      },
 174      "execution_count": 25,
 175      "metadata": {},
 176      "output_type": "execute_result"
 177     }
 178    ],
 179    "source": [
 180     "(2..2).to_a"
 181    ]
 182   },
 183   {
 184    "cell_type": "code",
 185    "execution_count": 31,
 186    "metadata": {
 187     "collapsed": false
 188    },
 189    "outputs": [
 190     {
 191      "data": {
 192       "text/plain": [
 193        ":concat_product"
 194       ]
 195      },
 196      "execution_count": 31,
 197      "metadata": {},
 198      "output_type": "execute_result"
 199     }
 200    ],
 201    "source": [
 202     "class Integer\n",
 203     "  def concat_product(n)\n",
 204     "    (1..n).flat_map {|m| (self * m).to_digits}.to_i\n",
 205     "  end\n",
 206     "end"
 207    ]
 208   },
 209   {
 210    "cell_type": "code",
 211    "execution_count": 34,
 212    "metadata": {
 213     "collapsed": false
 214    },
 215    "outputs": [
 216     {
 217      "data": {
 218       "text/plain": [
 219        "true"
 220       ]
 221      },
 222      "execution_count": 34,
 223      "metadata": {},
 224      "output_type": "execute_result"
 225     }
 226    ],
 227    "source": [
 228     "192.concat_product(3).pandigital?"
 229    ]
 230   },
 231   {
 232    "cell_type": "code",
 233    "execution_count": 35,
 234    "metadata": {
 235     "collapsed": false
 236    },
 237    "outputs": [
 238     {
 239      "data": {
 240       "text/plain": [
 241        "true"
 242       ]
 243      },
 244      "execution_count": 35,
 245      "metadata": {},
 246      "output_type": "execute_result"
 247     }
 248    ],
 249    "source": [
 250     "9.concat_product(5).pandigital?"
 251    ]
 252   },
 253   {
 254    "cell_type": "code",
 255    "execution_count": 48,
 256    "metadata": {
 257     "collapsed": false
 258    },
 259    "outputs": [
 260     {
 261      "data": {
 262       "text/plain": [
 263        "932718654"
 264       ]
 265      },
 266      "execution_count": 48,
 267      "metadata": {},
 268      "output_type": "execute_result"
 269     }
 270    ],
 271    "source": [
 272     "(1..10**5).to_a.product((2..5).to_a).select {|n, m| n.concat_product(m).pandigital?}.map {|n, m| n.concat_product(m)}.max"
 273    ]
 274   },
 275   {
 276    "cell_type": "code",
 277    "execution_count": null,
 278    "metadata": {
 279     "collapsed": true
 280    },
 281    "outputs": [],
 282    "source": []
 283   }
 284  ],
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 288    "language": "ruby",
 289    "name": "ruby"
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 294    "name": "ruby",
 295    "version": "2.4.0"
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 299  "nbformat_minor": 0
 300 }