LeetCode: 561. 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: 4Explanation: n is 2, and the maximum sum of pairs is 4.

Note:

1. n is a positive integer, which is in the range of [1, 10000].
2. All the integers in the array will be in the range of [-10000, 10000].

AC:

class Solution {public:    int min(int a,int b)    {        if(a>b)        return b;        return a;    }    int arrayPairSum(vector<int>& nums) {        sort(nums.begin(),nums.end());        int res = 0;        for(int i = 0;i<nums.size();i+=2)        {            res+=min(nums[i],nums[i+1]);        }        return res;    }};