561. Array Partition.py

"""
https://leetcode.com/problems/array-partition/

Given an integer array nums of 2n integers, group these integers into n pairs (a1, b1), (a2, b2), ..., (an, bn)
such that the sum of min(ai, bi) for all i is maximized. Return the maximized sum.

Example 1:
    Input: nums = [1,4,3,2]
    Output: 4
    Explanation: All possible pairings (ignoring the ordering of elements) are:
    1. (1, 4), (2, 3) -> min(1, 4) + min(2, 3) = 1 + 2 = 3
    2. (1, 3), (2, 4) -> min(1, 3) + min(2, 4) = 1 + 2 = 3
    3. (1, 2), (3, 4) -> min(1, 2) + min(3, 4) = 1 + 3 = 4
    So the maximum possible sum is 4.

Example 2:
    Input: nums = [6,2,6,5,1,2]
    Output: 9
    Explanation: The optimal pairing is (2, 1), (2, 5), (6, 6). min(2, 1) + min(2, 5) + min(6, 6) = 1 + 2 + 6 = 9.

"""


class Solution(object):
    def arrayPairSum(self, nums):
        nums.sort()
        res = 0
        for i in range(0, len(nums), 2):
            res += nums[i]
        return res


solution = Solution()
assert solution.arrayPairSum([1, 4, 3, 2]) == 4