LeetCode 561 Array Partition I

##题目 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].

Subscribe to see which companies asked this question. ##代码

func arrayPairSum(_ nums: [Int]) -> Int {
    guard nums.count % 2 == 0 else {
        return 0
    }
    var arr = nums
    arr.sort()
    var sum = 0
    for i in 0..<arr.count {
        if i % 2 == 0 {
            sum += arr[i]
        }
    }
    return sum
}