Classic problem #3978EasyArrayCounting
Unique Middle Element
Real-world version: Is the Middle Reading One of a KindTracked in this browser only
Read Unique Middle Element on LeetCode(opens in a new tab)
The statement here is our own: the same inputs, outputs and technique.
Readings are given as nums, and there is an odd number of them, so exactly one sits in the middle.
Return true when that middle reading appears nowhere else in the list.
Examples
Example 1
- Input
- nums = [4, 9, 27, 9, 4]
- Output
- true
The middle reading is 27, which appears nowhere else.
Example 2
- Input
- nums = [1, 2, 1]
- Output
- true
The middle reading is 2 and it is the only 2 on the list, even though the reading 1 is repeated.
Example 3
- Input
- nums = [8, 8, 3, 8, 8]
- Output
- true
The middle reading is 3, on its own, so the four eights around it make no difference.
Constraints
- 1 <= nums.length <= 100
- nums.length is odd
- 1 <= nums[i] <= 100
The signature
The editor starts with this. It matches the parent problem's shape, so a solution that works here works on a standard judge unchanged.
Python
def is_middle_element_unique(nums: list[int]) -> bool:Java
public boolean isMiddleElementUnique(int[] nums)Checking your plan…
How this problem was checked
- Passed: Reference solution run against 13 test cases: 13 passed
- Passed: 3 worked examples confirmed by running the code
- Passed: 0 eight-word sequences shared with the parent problem's text
- Passed: Agrees with an independent brute-force solution on random inputs
- Passed: Test set shown to catch deliberately broken solutions
- Passed: Reviewed by a separate quality pass
- Passed: Function arity matches the parent problem's