LC-0268 Easy LeetCode

268. Missing Number

Array Hash Table Math Binary Search Bit Manipulation Sorting

Read the full problem statement on LeetCode.

Difficulty: easy Acceptance: 70% Topics: Array, Hash Table, Math, Binary Search, Bit Manipulation, Sorting

Reading material

Arrays & Hashing 12 min Math & Geometry 12 min Binary Search 12 min

Reference solution (spoiler · python)

# Time:  O(n)
# Space: O(1)

import operator


class Solution(object):
    def missingNumber(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        return reduce(operator.xor, nums,
                      reduce(operator.xor, xrange(len(nums) + 1)))


class Solution2(object):
    def missingNumber(self, nums):
        return sum(xrange(len(nums)+1)) - sum(nums)

Solution from kamyu104/LeetCode-Solutions · MIT