Array Partition I

Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (an, bn) which makes sum of min(ai, bi) 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: n is a positive integer, which is in the range of [1, 10000]. All the integers in the array will be in the range of [-10000, 10000].

Solution: Soring

int arrayPairSum(vector<int>& nums) {
    sort(nums.begin(), nums.end());
    int maxSum = 0;
    for(int i=0; i<nums.size(); i+=2) {
        maxSum += nums[i];
    }
    return maxSum;
}