mirror of
https://github.com/prdlk/leetcode.git
synced 2026-09-17 15:36:26 +00:00
83 lines
1.5 KiB
Python
83 lines
1.5 KiB
Python
|
"""
|
||
|
|
268. Missing Number
|
||
|
|
Difficulty: Easy
|
||
|
|
https://leetcode.com/problems/missing-number/
|
||
|
|
|
||
|
|
──────────────────────────────────────────────────
|
||
|
|
|
||
|
|
Given an array nums containing n distinct numbers in the range [0,
|
||
|
|
n], return the only number in the range that is missing from the
|
||
|
|
array.
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
Example 1:
|
||
|
|
|
||
|
|
Input: nums = [3,0,1]
|
||
|
|
|
||
|
|
Output: 2
|
||
|
|
|
||
|
|
Explanation:
|
||
|
|
|
||
|
|
n = 3 since there are 3 numbers, so all numbers are in the range
|
||
|
|
[0,3]. 2 is the missing number in the range since it does not appear
|
||
|
|
in nums.
|
||
|
|
|
||
|
|
Example 2:
|
||
|
|
|
||
|
|
Input: nums = [0,1]
|
||
|
|
|
||
|
|
Output: 2
|
||
|
|
|
||
|
|
Explanation:
|
||
|
|
|
||
|
|
n = 2 since there are 2 numbers, so all numbers are in the range
|
||
|
|
[0,2]. 2 is the missing number in the range since it does not appear
|
||
|
|
in nums.
|
||
|
|
|
||
|
|
Example 3:
|
||
|
|
|
||
|
|
Input: nums = [9,6,4,2,3,5,7,0,1]
|
||
|
|
|
||
|
|
Output: 8
|
||
|
|
|
||
|
|
Explanation:
|
||
|
|
|
||
|
|
n = 9 since there are 9 numbers, so all numbers are in the range
|
||
|
|
[0,9]. 8 is the missing number in the range since it does not appear
|
||
|
|
in nums.
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
Constraints:
|
||
|
|
|
||
|
|
• n == nums.length
|
||
|
|
|
||
|
|
• 1 <= n <= 10^4
|
||
|
|
|
||
|
|
• 0 <= nums[i] <= n
|
||
|
|
|
||
|
|
• All the numbers of nums are unique.
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
Follow up: Could you implement a solution using only O(1) extra space
|
||
|
|
complexity and O(n) runtime complexity?
|
||
|
|
"""
|
||
|
|
|
||
|
|
|
||
|
|
class Solution:
|
||
|
|
def missingNumber(self, nums: List[int]) -> int:
|
||
|
|
n = len(nums)
|
||
|
|
expected_sum = (n * (n + 1)) // 2
|
||
|
|
actual_sum = sum(nums)
|
||
|
|
return expected_sum - actual_sum
|