remove-element_27.py

# Given an integer array nums and an integer val, remove all occurrences of val in nums in-place. The order of the elements may be changed. Then return the number of elements in nums which are not equal to val.

# Consider the number of elements in nums which are not equal to val be k, to get accepted, you need to do the following things:

# Change the array nums such that the first k elements of nums contain the elements which are not equal to val. The remaining elements of nums are not important as well as the size of nums.
# Return k.
# Custom Judge:

# The judge will test your solution with the following code:

# int[] nums = [...]; // Input array
# int val = ...; // Value to remove
# int[] expectedNums = [...]; // The expected answer with correct length.
#                             // It is sorted with no values equaling val.

# int k = removeElement(nums, val); // Calls your implementation

# assert k == expectedNums.length;
# sort(nums, 0, k); // Sort the first k elements of nums
# for (int i = 0; i < actualLength; i++) {
#     assert nums[i] == expectedNums[i];
# }
# If all assertions pass, then your solution will be accepted.


# Example 1:

# Input: nums = [3,2,2,3], val = 3
# Output: 2, nums = [2,2,_,_]
# Explanation: Your function should return k = 2, with the first two elements of nums being 2.
# It does not matter what you leave beyond the returned k (hence they are underscores).
# Example 2:

# Input: nums = [0,1,2,2,3,0,4,2], val = 2
# Output: 5, nums = [0,1,4,0,3,_,_,_]
# Explanation: Your function should return k = 5, with the first five elements of nums containing 0, 0, 1, 3, and 4.
# Note that the five elements can be returned in any order.
# It does not matter what you leave beyond the returned k (hence they are underscores).

# ---------------------------------------Runtime 59 ms Beats 5.60% Memory 16.3 MB Beats 17.52%---------------------------------------


from typing import List


# Solution #1
class Solution:
    def removeElement(self, nums: List[int], val: int) -> int:
        l, r = 0, len(nums) - 1
        while l <= r:
            if nums[l] == val:
                nums.pop(l)
                r -= 1
                l -= 1
            if nums:
                if nums[r] == val:
                    nums.pop(r)
            r -= 1
            l += 1
        return len(nums)


# ---------------------------------------Runtime 47 ms Beats 19.33% Memory 16.3 MB Beats 17.52%---------------------------------------


# Soltion @softray
def removeElement(self, nums, val):
    start, end = 0, len(nums) - 1
    while start <= end:
        if nums[start] == val:
            nums[start], nums[end], end = nums[end], nums[start], end - 1
        else:
            start += 1
    return start


# ---------------------------------------Runtime 55 ms Beats 5.60% Memory 16.3 MB Beats 5.23%---------------------------------------


# Solution @Pritz10
class Solution:
    def removeElement(self, nums: List[int], val: int) -> int:
        while val in nums:
            nums.remove(val)