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].
题目本质上就是排序,取前n个的和
class Solution {
public:
int arrayPairSum(vector<int>& nums) {
if(nums.empty() || nums.size()%2 !=0)
return 0;
int sum =0;
std::sort(nums.begin(), nums.end());
for(int n=0;n<nums.size();n+=2)
{
sum = sum + nums[n];
}
return sum;
}
};