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1262. Greatest Sum Divisible by Three

Difficulty Topics

Description

Given an integer array nums, return the maximum possible sum of elements of the array such that it is divisible by three.

 

Example 1:

Input: nums = [3,6,5,1,8]
Output: 18
Explanation: Pick numbers 3, 6, 1 and 8 their sum is 18 (maximum sum divisible by 3).

Example 2:

Input: nums = [4]
Output: 0
Explanation: Since 4 is not divisible by 3, do not pick any number.

Example 3:

Input: nums = [1,2,3,4,4]
Output: 12
Explanation: Pick numbers 1, 3, 4 and 4 their sum is 12 (maximum sum divisible by 3).

 

Constraints:

  • 1 <= nums.length <= 4 * 104
  • 1 <= nums[i] <= 104

Solution

greatest-sum-divisible-by-three.py
class Solution:
    def maxSumDivThree(self, nums: List[int]) -> int:
        n = len(nums)
        dp = [0, 0, 0]

        for num in nums:

            for i in dp[:]:
                dp[(i+num)%3] = max(dp[(i+num)%3], num + i)


        return dp[0]
greatest-sum-divisible-by-three.cpp
class Solution {
public:
    int maxSumDivThree(vector<int>& nums) {
        vector<int> dp {0,0,0}, dp2;

        for (int num : nums){
            dp2 = dp;

            for (int i : dp2){
                dp[(num+i)%3] = max(dp[(num+i)%3], num+i);
            }
        }

        return dp[0];
    }
};