LeetCode One Question of the Day 561. Array Split I

561. Array Split I

A given length of 2nthe array of integers nums, your task is divided into a number of these npairs, e.g. (a1, b1), (a2, b2), ..., (an, bn), from such 1to nthe min(ai, bi)sum of the maximum.

Return the maximum sum.

Example 1:

输入：nums = [1,4,3,2]
输出：4
解释：所有可能的分法（忽略元素顺序）为：
1. (1, 4), (2, 3) -> min(1, 4) + min(2, 3) = 1 + 2 = 3
2. (1, 3), (2, 4) -> min(1, 3) + min(2, 4) = 1 + 2 = 3
3. (1, 2), (3, 4) -> min(1, 2) + min(3, 4) = 1 + 3 = 4
所以最大总和为 4

Example 2:

输入：nums = [6,2,6,5,1,2]
输出：9
解释：最优的分法为 (2, 1), (2, 5), (6, 6). min(2, 1) + min(2, 5) + min(6, 6) = 1 + 2 + 6 = 9

prompt:

• 1 <= n <= 10^4
• nums.length == 2 * n
• -10^4 <= nums[i] <= 10^4

Method 1: Sort

Problem-solving ideas

• After sorting, take the even number and accumulate

Reference Code

public int arrayPairSum(int[] nums) {
    
    
    Arrays.sort(nums);
    int ret = 0;
    for (int i = 0; i < nums.length; i += 2) {
    
    
        ret += nums[i];
    }
    return ret;
}

Results of the