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).

题目意思：将数组每相邻两个数组成对，然后在对在挑出最小值相加，最后返回sum;

思路:把数组按从小到大排好队，然后分别将偶数项相加。

代码如下

class Solution {
    public int arrayPairSum(int[] nums) {
        Arrays.sort(nums);
        int sum=0;
        for(int i=0;i<nums.length;i+=2){
            sum+=nums[i];
        }
        return sum;
    }
}