268.缺失数字.py

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# @lc app=leetcode.cn id=268 lang=python3
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# [268] 缺失数字
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# https://leetcode-cn.com/problems/missing-number/description/
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# algorithms
# Easy (54.05%)
# Likes:    222
# Dislikes: 0
# Total Accepted:    52.9K
# Total Submissions: 97K
# Testcase Example:  '[3,0,1]'
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# 给定一个包含 0, 1, 2, ..., n 中 n 个数的序列，找出 0 .. n 中没有出现在序列中的那个数。
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# 示例 1:
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# 输入: [3,0,1]
# 输出: 2
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# 示例 2:
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# 输入: [9,6,4,2,3,5,7,0,1]
# 输出: 8
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# 说明:
# 你的算法应具有线性时间复杂度。你能否仅使用额外常数空间来实现?
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#

# @lc code=start
class Solution:
    def missingNumber(self, nums: List[int]) -> int:
        missing = len(nums)
        for i, n in enumerate(nums):
            missing ^= i ^ n
        return missing
# @lc code=end