LeetCode 561. Array Partition I

Array Partition I

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题目描述:

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 = min(1, 2) + min(3, 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].

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题目大意:

给定2n个元素的数字，让数字两两组合，组成n对，取出每一对中对较小的那个数，求和。这个和最大是多少。
排序后按顺序两两相加求和即可。

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题目代码:

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