Array Partition#11664
Given an integer array of integers.
Group these integers into pairs (a_1, b_1), (a_2, b_2), \ldots, (a_n, b_n) such that the sum of min(a_i, b_i) for all is maximized.
The first line contains one number n~(n \le 10^5). The second line contains integers, each no more than 10^5 by absolute value.
Print the maximum possible value of the sum.
Example 1