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    "In a string `s` of lowercase letters, these letters form consecutive groups of\n",
    "the same character.\n",
    "\n",
    "For example, a string like `s = \"abbxxxxzyy\"` has the groups `\"a\"`, `\"bb\"`,\n",
    "`\"xxxx\"`, `\"z\"`, and `\"yy\"`.\n",
    "\n",
    "A group is identified by an interval `[start, end]`, where `start` and `end`\n",
    "denote the start and end indices (inclusive) of the group. In the above\n",
    "example, `\"xxxx\"` has the interval `[3,6]`.\n",
    "\n",
    "A group is considered  **large**  if it has 3 or more characters.\n",
    "\n",
    "Return  _the intervals of every **large** group sorted in  **increasing order\n",
    "by start index**_.\n",
    "\n",
    "\n",
    "\n",
    "**Example 1:**\n",
    "\n",
    "\n",
    "\n",
    "    Input: s = \"abbxxxxzzy\"\n",
    "    Output: [[3,6]]\n",
    "    **Explanation** : \"xxxx\" is the only large group with start index 3 and end index 6.\n",
    "\n",
    "\n",
    "**Example 2:**\n",
    "\n",
    "\n",
    "\n",
    "    Input: s = \"abc\"\n",
    "    Output: []\n",
    "    **Explanation** : We have groups \"a\", \"b\", and \"c\", none of which are large groups.\n",
    "\n",
    "\n",
    "**Example 3:**\n",
    "\n",
    "\n",
    "\n",
    "    Input: s = \"abcdddeeeeaabbbcd\"\n",
    "    Output: [[3,5],[6,9],[12,14]]\n",
    "    **Explanation** : The large groups are \"ddd\", \"eeee\", and \"bbb\".\n",
    "\n",
    "\n",
    "**Example 4:**\n",
    "\n",
    "\n",
    "\n",
    "    Input: s = \"aba\"\n",
    "    Output: []\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "**Constraints:**\n",
    "\n",
    "  * `1 <= s.length <= 1000`\n",
    "  * `s` contains lower-case English letters only."
   ],
   "metadata": {}
  },
  {
   "outputs": [
    {
     "output_type": "execute_result",
     "data": {
      "text/plain": "large_group_positions (generic function with 1 method)"
     },
     "metadata": {},
     "execution_count": 1
    }
   ],
   "cell_type": "code",
   "source": [
    "# @lc code=start\n",
    "using LeetCode\n",
    "\n",
    "function large_group_positions(s::String)::Vector{Vector{Int}}\n",
    "    ch = s[1]\n",
    "    bg = 1\n",
    "    res = Vector{Int}[]\n",
    "    for i in 2:length(s)\n",
    "        if s[i] != ch\n",
    "            if i - bg > 2\n",
    "                push!(res, [bg - 1, i - 2]) #1-index to 0-index\n",
    "            end\n",
    "            ch = s[i]\n",
    "            bg = i\n",
    "        end\n",
    "    end\n",
    "    res\n",
    "end\n",
    "# @lc code=end"
   ],
   "metadata": {},
   "execution_count": 1
  },
  {
   "cell_type": "markdown",
   "source": [
    "---\n",
    "\n",
    "*This notebook was generated using [Literate.jl](https://github.com/fredrikekre/Literate.jl).*"
   ],
   "metadata": {}
  }
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