# Solution: First Non-Repeating Integer in a List

Let’s solve the First NonRepeating Integer in a List problem.

## We'll cover the following

## Statement

Given a list `nums`

, find the first nonrepeating integer in it.

**Constraints:**

$1 \leq$ `nums.length`

$\leq 10^3$ $-10^4 \leq$ `nums[i]`

$\leq 10^4$

## Solution

The brute force approach involves comparing elements pairwise in the list to check if a given element is unique. Here are the steps of the algorithm:

Traverse the list with the pointer

`p1`

from the beginning to the end.For each element pointed by

`p1`

, initialize another pointer,`p2`

, to the start of the list.Use

`p2`

to traverse the list from the beginning to the end. During this traversal, check if the elements at the locations pointed by`p1`

and`p2`

are the same, ensuring`p1`

and`p2`

are not pointing to the same location.If an element pointed by

`p1`

is found to be equal to an element pointed by`p2`

(where`p1`

does not point to the same location as`p2`

), it indicates that the element at`p1`

is not unique. Break the inner loop (the traversal with`p2`

) and move`p1`

to the next element to restart the check for uniqueness.If

`p2`

completes its traversal (reaches the end of the list) without finding a duplicate, the element at`p1`

is unique. We can then return this element.Repeat this process until

`p1`

has traversed the entire list.

Let’s look at the illustrations below to better understand the solution:

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