22. 括号生成.ipynb

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    "class Solution:\n",
    "    def generateParenthesis(self, n: int) -> [str]:\n",
    "        def backtrack(string, left, right):\n",
    "            if left+right == 2*n:\n",
    "                res.append(string)\n",
    "            if left < n:\n",
    "                backtrack(string+'(', left+1, right)\n",
    "            if right < left:\n",
    "                backtrack(string+')', left, right+1)\n",
    "        res = []\n",
    "        if n > 0:\n",
    "            backtrack('', 0, 0)\n",
    "        return res\n",
    "s = Solution()\n",
    "s.generateParenthesis(3)"
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