RomanToInt.ipynb

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    "Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.\n",
    "Given a roman numeral, convert it to an integer.\n",
    "\n",
    " \n",
    "\n",
    "Example 1:\n",
    "\n",
    "Input: s = \"III\"\n",
    "Output: 3\n",
    "Explanation: III = 3.\n",
    "Example 2:\n",
    "\n",
    "Input: s = \"LVIII\"\n",
    "Output: 58\n",
    "Explanation: L = 50, V= 5, III = 3.\n",
    "\n",
    "Example 3:\n",
    "\n",
    "Input: s = \"MCMXCIV\"\n",
    "Output: 1994\n",
    "Explanation: M = 1000, CM = 900, XC = 90 and IV = 4."
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    "def romanToInt(s):\n",
    "        \n",
    "    roman_add = {'I': 1, 'V': 5, 'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000}\n",
    "    roman_sub = {'IV': 4, 'IX': 9, 'XL': 40, 'XC': 90, 'CD': 400, 'CM': 900}\n",
    "    sum = 0\n",
    "    i = 0\n",
    "       \n",
    "    while i < len(s):\n",
    "          \n",
    "        if (s[i] == 'I' or s[i] == 'X' or s[i] == 'C') and i != len(s)-1: # when sub needed\n",
    "            if s[i]+s[i+1] in roman_sub: # if pair in romansub\n",
    "                sum += roman_sub[s[i]+s[i+1]] # add value of pair\n",
    "                i+= 2 # increment by 2 since two letters were used\n",
    "            else: # add value of I or X or C\n",
    "                sum += roman_add[s[i]]\n",
    "                i += 1\n",
    "                \n",
    "                \n",
    "        elif s[i] in roman_add: # if not I or X or C add value\n",
    "                \n",
    "            sum += roman_add[s[i]]\n",
    "            i += 1\n",
    "        \n",
    "        \n",
    "\n",
    "                \n",
    "    return sum\n",
    "                "
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       "1994"
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    "romanToInt('MCMXCIV')"
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   "source": [
    "s ='yub'"
   ]
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