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561. Array Partition I (Easy)

Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a₁, b₁), (a₂, b₂), ..., (a_n, b_n) which makes sum of min(a_i, b_i) 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:

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].

Related Topics

[Array]

Hints

Hint 1

Obviously, brute force won't help here. Think of something else, take some example like 1,2,3,4.

Hint 2

How will you make pairs to get the result? There must be some pattern.

Hint 3

Did you observe that- Minimum element gets add into the result in sacrifice of maximum element.

Hint 4

Still won't able to find pairs? Sort the array and try to find the pattern.