Delete and Earn

You are given an integer array nums. You want to maximize the number of points you get by performing the following operation any number of times:

• Pick any nums[i] and delete it to earn nums[i] points. Afterwards, you must delete every element equal to nums[i] - 1 and every element equal to nums[i] + 1.

Return the maximum number of points you can earn by applying the above operation some number of times.

Example 1:

Input: nums = [3,4,2]
Output: 6
Explanation: You can perform the following operations:

• Delete 4 to earn 4 points. Consequently, 3 is also deleted. nums = [2].
• Delete 2 to earn 2 points. nums = []. You earn a total of 6 points.

Example 2:

Input: nums = [2,2,3,3,3,4]
Output: 9
Explanation: You can perform the following operations:

• Delete a 3 to earn 3 points. All 2's and 4's are also deleted. nums = [3,3].
• Delete a 3 again to earn 3 points. nums = [3].
• Delete a 3 once more to earn 3 points. nums = []. You earn a total of 9 points.

Constraints:

• 1 <= nums.length <= 2 * 104
• 1 <= nums[i] <= 104

SOLUTION:

from collections import Counter

class Solution:
    def deleteAndEarn(self, nums: List[int]) -> int:
        ctr = Counter(nums)
        prev = curr = 0
        for num in range(10001):
            prev, curr = curr, max(prev + num * ctr[num], curr)
        return curr