2342. Max Sum of a Pair With Equal Sum of Digits

Description

You are given a 0-indexed array nums consisting of positive integers. You can choose two indices i and j, such that i != j, and the sum of digits of the number nums[i] is equal to that of nums[j].

Return the maximum value of nums[i] + nums[j] that you can obtain over all possible indices i and j that satisfy the conditions.

 

Example 1:

Input: nums = [18,43,36,13,7]
Output: 54
Explanation: The pairs (i, j) that satisfy the conditions are:
- (0, 2), both numbers have a sum of digits equal to 9, and their sum is 18 + 36 = 54.
- (1, 4), both numbers have a sum of digits equal to 7, and their sum is 43 + 7 = 50.
So the maximum sum that we can obtain is 54.

Example 2:

Input: nums = [10,12,19,14]
Output: -1
Explanation: There are no two numbers that satisfy the conditions, so we return -1.

 

Constraints:

• 1 <= nums.length <= 105
• 1 <= nums[i] <= 109

Solution

max-sum-of-a-pair-with-equal-sum-of-digits.py

class Solution:
    def maximumSum(self, nums: List[int]) -> int:
        n = len(nums)
        cnt = defaultdict(list)

        for x in nums:
            cnt[sum(int(k) for k in str(x))].append(x)

        res = -1

        for values in cnt.values():
            if len(values) >= 2:
                values.sort()
                res = max(res, values[-1] + values[-2])


        return res