A-剑指offer/剑指 Offer 56 - II. 数组中数字出现的次数 II.ipynb

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    "[剑指 Offer 56 - II. 数组中数字出现的次数 II](https://leetcode-cn.com/problems/shu-zu-zhong-shu-zi-chu-xian-de-ci-shu-ii-lcof/)\n",
    "\n",
    "```\n",
    "在一个数组 nums 中除一个数字只出现一次之外，其他数字都出现了三次。请找出那个只出现一次的数字。\n",
    "\n",
    " \n",
    "\n",
    "示例 1：\n",
    "\n",
    "输入：nums = [3,4,3,3]\n",
    "输出：4\n",
    "\n",
    "示例 2：\n",
    "\n",
    "输入：nums = [9,1,7,9,7,9,7]\n",
    "输出：1\n",
    "```"
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    "class Solution:\n",
    "    def singleNumber(self, nums: List[int]) -> int:\n",
    "        if len(nums)==0:\n",
    "            return 0\n",
    "\n",
    "        numarr = [0 for i in range(32)]\n",
    "        for i in range(len(nums)):\n",
    "            bitmask = 1\n",
    "            for j in range(31, -1, -1):\n",
    "                bit = nums[i] & bitmask\n",
    "                if bit != 0:\n",
    "                    numarr[j] += 1\n",
    "                bitmask = bitmask << 1\n",
    "\n",
    "        print(numarr)\n",
    "        result = 0\n",
    "        for i in range(32):\n",
    "            result = result << 1\n",
    "            result += numarr[i] % 3\n",
    "\n",
    "\n",
    "        return result"
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