{
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Number 3"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "https://leetcode.com/problems/longest-substring-without-repeating-characters/"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Solution:\n",
    "    def lengthOfLongestSubstring(self, s: str) -> int:\n",
    "        i1 = 0\n",
    "        s_list = list(s)\n",
    "        \n",
    "        len_s = len(s_list)\n",
    "        max_string_size = 0\n",
    "\n",
    "        for i1 in range(len_s):\n",
    "            print(i1)\n",
    "            char_list = [] # check if character already in list\n",
    "            for i2 in range(i1, len_s):\n",
    "                cur_char = s_list[i2]\n",
    "                if cur_char not in char_list:\n",
    "                    char_list.append(cur_char)\n",
    "                else:\n",
    "                    # Time to recalculate\n",
    "                    break\n",
    "            cur_string_size = len(char_list) \n",
    "            max_string_size = cur_string_size if cur_string_size > max_string_size else max_string_size\n",
    "\n",
    "        return max_string_size\n",
    "\n",
    "            \n",
    "\n",
    "\n",
    "        "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "1\n",
      "2\n",
      "3\n",
      "4\n",
      "5\n",
      "6\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "6"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s = Solution()\n",
    "s.lengthOfLongestSubstring(\"abhiram\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Let's see if this can be faster**\n",
    "\n",
    "Update - This actually threw a TLE on a really long input. Fail. ⛔️"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Solution2:\n",
    "    def lengthOfLongestSubstring2(self, s: str) -> int:\n",
    "        i1 = 0\n",
    "        s_list = list(s)\n",
    "        \n",
    "        len_s = len(s_list)\n",
    "        max_string_size = 0\n",
    "\n",
    "        for i1 in range(len_s):\n",
    "            for i2 in range(len_s, i1-1,-1):\n",
    "                cur_word = s_list[i1:i2]\n",
    "                len_set = len(set(cur_word))\n",
    "                len_list = len((cur_word))\n",
    "                if len_set < len_list:\n",
    "                    pass\n",
    "                else:\n",
    "                    cur_string_size = len(cur_word) \n",
    "                    max_string_size = cur_string_size if cur_string_size > max_string_size else max_string_size\n",
    "                    break\n",
    "\n",
    "        return max_string_size"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "6"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s = Solution2()\n",
    "s.lengthOfLongestSubstring2(\"abhiram\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Same double pointer trick, but this time start from the reverse**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Solution3:\n",
    "    def lengthOfLongestSubstring3(self, s: str) -> int:\n",
    "        i1 = 0\n",
    "        s_list = list(s)\n",
    "        \n",
    "        len_s = len(s_list)\n",
    "        max_string_size = 0\n",
    "\n",
    "        for i1 in range(len_s):\n",
    "            char_list = [] # check if character already in list\n",
    "            if max_string_size > len_s - i1:\n",
    "                break\n",
    "            for i2 in range(i1, len_s):\n",
    "                cur_char = s_list[i2]\n",
    "                if cur_char not in char_list:\n",
    "                    char_list.append(cur_char)\n",
    "                else:\n",
    "                    # Time to recalculate\n",
    "                    break\n",
    "            cur_string_size = len(char_list) \n",
    "            max_string_size = cur_string_size if cur_string_size > max_string_size else max_string_size\n",
    "            \n",
    "\n",
    "        return max_string_size\n",
    "\n",
    "            \n",
    "\n",
    "\n",
    "        "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "6"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s = Solution3()\n",
    "s.lengthOfLongestSubstring3(\"abhiram\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "6"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "class Solution4:\n",
    "    def lengthOfLongestSubstring4(self, s: str) -> int:\n",
    "        i1 = 0\n",
    "        s_list = list(s)\n",
    "        \n",
    "        len_s = len(s_list)\n",
    "        max_string_size = 0\n",
    "\n",
    "        for i1 in range(len_s):\n",
    "            char_list = [] # check if character already in list\n",
    "            char_list2 = []\n",
    "            if max_string_size > len_s - i1:\n",
    "                return max_string_size\n",
    "            for i2 in range(i1, len_s):\n",
    "                cur_char = s_list[i2]\n",
    "                if cur_char not in char_list:\n",
    "                    char_list.append(cur_char)\n",
    "                else:\n",
    "                    # Time to recalculate\n",
    "                    break\n",
    "            for i3 in range(i1+1, len_s):\n",
    "                cur_char = s_list[i3]\n",
    "                if cur_char not in char_list2:\n",
    "                    char_list2.append(cur_char)\n",
    "                else:\n",
    "                    # Time to recalculate\n",
    "                    break\n",
    "            i1 = i1+1\n",
    "            cur_string_size = len(char_list) \n",
    "            cur_string_size2 = len(char_list2) \n",
    "            max_string_size = max(max_string_size,cur_string_size,cur_string_size2 )\n",
    "            \n",
    "\n",
    "        return max_string_size\n",
    "\n",
    "s = Solution4()\n",
    "s.lengthOfLongestSubstring4(\"abhiram\")"
   ]
  }
 ],
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