561. Array Partition I

• Difficulty: Easy

• Topics: Array

• Similar Questions:

Problem:

Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a₁, b₁), (a₂, b₂), ..., (a_n, b_n) which makes sum of min(a_i, b_i) for all i from 1 to n as large as possible.

Example 1:

Input: [1,4,3,2]

Output: 4
Explanation: n is 2, and the maximum sum of pairs is 4 = min(1, 2) + min(3, 4).

Note:

Solutions:

class Solution {
public:
    int arrayPairSum(vector<int>& nums) {
        sort(nums.begin(), nums.end());

        int sum = 0;
        for (int i = 0; i < nums.size(); i = i + 2) {
            sum += nums[i];
        }

        return sum;
    }
};