First Unique Element Index

Easy

Hash TablesArraysTrees

Problem

Given an array of integers nums, return the index of the first element whose value appears exactly once in the array. If no such element exists, return -1. The function should take a list of integers and return a single integer index.

Constraints

1 <= len(nums) <= 10^5
-10^9 <= nums[i] <= 10^9
An O(n) solution is expected

Problem

Constraints

1 <= len(nums) <= 10^5
-10^9 <= nums[i] <= 10^9
An O(n) solution is expected

Practice Python

Python 3.10

Open on desktop for the full Python editor with syntax highlighting and autocomplete.

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Asked 2mo ago|

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First Unique Element Index

Easy

Hash TablesArraysTrees

Problem

Constraints

1 <= len(nums) <= 10^5
-10^9 <= nums[i] <= 10^9
An O(n) solution is expected

Problem

Constraints

1 <= len(nums) <= 10^5
-10^9 <= nums[i] <= 10^9
An O(n) solution is expected

Practice Python

Python 3.10

Open on desktop for the full Python editor with syntax highlighting and autocomplete.

Up next

First Unique Element IndexEasy

First Duplicate Value IndexEasy

Next question

First Unique Element Index | Dataford Interview Questions