leetcode-561(Array Partition I)

Posted 2023-02-25 dongmeima_coder

Decription

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.

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].

Solution

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

Conclude

2n个数据分成n组，每组两个数据。从每组数据中找出最小的，相加求最大和。

先排序，然后抽取出奇数位的数相加即可得到结果。