Remove Element

Explore how to apply the two-pointer technique to remove all instances of a given value from an integer array without extra memory. Understand the problem constraints and implement an in-place solution that modifies the array and returns the count of remaining valid elements.

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Statement

You are given an integer array, nums, and an integer, val. Your task is to remove all occurrences of val from nums in place, meaning no additional memory allocation should be used. The relative order of the elements in the array may be changed. After modifying the array, return the number of elements that are not equal to val.

Let $k$ represent the number of elements in nums that are not equal to val. To successfully solve this problem, you need to ensure the following:

Modify the array, nums, such that the first $k$ ...