740. Delete and Earn

Given an array nums of integers, you can perform operations on the array.

In each operation, you pick any nums[i] and delete it to earn nums[i] points. After, you must delete every element equal to nums[i] - 1 or nums[i] + 1.

You start with 0 points. Return the maximum number of points you can earn by applying such operations.

Example 1:

Input: nums = [3, 4, 2]
Output: 6
Explanation:
Delete 4 to earn 4 points, consequently 3 is also deleted.
Then, delete 2 to earn 2 points. 6 total points are earned.

Example 2:

Input: nums = [2, 2, 3, 3, 3, 4]
Output: 9
Explanation:
Delete 3 to earn 3 points, deleting both 2's and the 4.
Then, delete 3 again to earn 3 points, and 3 again to earn 3 points.
9 total points are earned.

Note:

• The length of nums is at most 20000.
• Each element nums[i] is an integer in the range [1, 10000].

# @lc code=start
using LeetCode

function delete_and_earn(nums::Vector{Int})
    if length(nums) == 0
        return 0
    elseif length(nums) == 1
        return nums[1]
    end
    cntr = fill(0, maximum(nums))
    for num in nums
        cntr[num] += num
    end
    fst, scd = cntr[1], max(cntr[2], cntr[1])
    for i in 3:length(cntr)
        fst, scd = scd, max(fst + cntr[i], scd)
    end
    return scd
end
# @lc code=end

delete_and_earn (generic function with 1 method)

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