1200. Minimum Absolute Difference.java

/*
Given an array of distinct integers arr, find all pairs of elements with the minimum absolute difference of any two elements. 

Return a list of pairs in ascending order(with respect to pairs), each pair [a, b] follows

a, b are from arr
a < b
b - a equals to the minimum absolute difference of any two elements in arr
 

Example 1:

Input: arr = [4,2,1,3]
Output: [[1,2],[2,3],[3,4]]
Explanation: The minimum absolute difference is 1. List all pairs with difference equal to 1 in ascending order.
Example 2:

Input: arr = [1,3,6,10,15]
Output: [[1,3]]
Example 3:

Input: arr = [3,8,-10,23,19,-4,-14,27]
Output: [[-14,-10],[19,23],[23,27]]
 

Constraints:

2 <= arr.length <= 10^5
-10^6 <= arr[i] <= 10^6
*/

//Solution:
class Solution {
    public List<List<Integer>> minimumAbsDifference(int[] arr) {
        Arrays.sort(arr);
        List<List<Integer>> res = new ArrayList();
        int min = Integer.MAX_VALUE;
        for(int i = 1; i<arr.length;i++){
            int diff = arr[i] - arr[i-1];
            if(diff == min){
                res.add(Arrays.asList(arr[i-1], arr[i]));
                
            }else if(diff < min){
                res.clear();
                res.add(Arrays.asList(arr[i-1] , arr[i]));
                min = diff;
            }
        }
        
        return res;
    }
}