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Missing Number
Learn how to solve the 'Missing Number' problem. This detailed resource details brute force and optimized approaches.
Problem Statement
Easy
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.
Write a function missingNumber(nums: List[int]) -> int.
Constraints
- •n == len(nums)
- •1 <= n <= 10^4
- •0 <= nums[i] <= n
- •All the numbers of nums are unique
Examples
Example 1
Input
nums = [3,0,1]
Output
2
Explanation
n = 3, range [0,3]. 2 is missing.
Example 2
Input
nums = [0,1]
Output
2
Explanation
n = 2, range [0,2]. 2 is missing.
Example 3
Input
nums = [9,6,4,2,3,5,7,0,1]
Output
8
Explanation
n = 9, range [0,9]. 8 is missing.
Need a Hint?
Analyze the input constraints. Try sorting first (O(n log n)) or using a hash map/set to track seen elements in O(n) time.
Edge Cases to Watch
- Empty list or null input variables
- Single item lists/arrays
- Extremely large input bounds causing integer or stack overflow
Ready to Solve?
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