1133. Largest Unique Number

https://leetcode.com/problems/largest-unique-number

Description

Given an integer array nums, return the largest integer that only occurs once. If no integer occurs once, return -1.

Example 1:

**Input:** nums = [5,7,3,9,4,9,8,3,1]
**Output:** 8
**Explanation:** The maximum integer in the array is 9 but it is repeated. The number 8 occurs only once, so it is the answer.

Example 2:

**Input:** nums = [9,9,8,8]
**Output:** -1
**Explanation:** There is no number that occurs only once.

Constraints:

• 1 <= nums.length <= 2000

• 0 <= nums[i] <= 1000

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