Remove Element

Deleting from the middle of an array is slow because every later element has to shift. A common trick is to not shrink the list at all: overwrite the values you want to keep at the front and return how many there are. Callers then only read the first k slots.

Given a list nums and an integer val, remove every occurrence of val in place. Return the number k of remaining elements. After your function returns, the first k positions of nums must hold exactly the kept values (in any order); whatever sits beyond position k does not matter.

Examples

Input:  nums = [3, 2, 2, 3], val = 3
Output: 2
After:  the first 2 slots of nums contain 2 and 2

Input:  nums = [0, 1, 2, 2, 3, 0, 4, 2], val = 2
Output: 5
After:  the first 5 slots of nums contain 0, 0, 1, 3, 4 in some order

Constraints

• 0 <= len(nums) <= 1000
• Modify nums in place; the tests read nums[:k] after the call.

Goals

• Overwrite unwanted values in place and report how many elements remain
• Recognise the 'return the new length' convention used by many array problems