LeetCode 1200. Minimum Absolute Difference

考点	难度
Sorting	Easy

题目

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

思路

先排序，找到两个相邻数字之间最小的差，再遍历找到符合这个差的数。

答案

public List<List<Integer>> minimumAbsDifference(int[] arr) {
        // Sort the original array 
        Arrays.sort(arr);
        List<List<Integer>> answer = new ArrayList();

        // Initialize minimum difference as a huge integer in order not 
        // to miss the absolute difference of the first pair. 
        int minPairDiff = Integer.MAX_VALUE;
        
        // Traverse the sorted array and calcalute the minimum absolute difference.
        for (int i = 0; i < arr.length - 1; ++i) {
            minPairDiff = Math.min(minPairDiff, arr[i + 1] - arr[i]);
        }

        // Traverse the sorted array and check every pair again, if 
        // the absolute difference equals the minimum difference, 
        // add this pair to the answer list.        
        for (int i = 0; i < arr.length - 1; ++i) {
            if (arr[i + 1] - arr[i] == minPairDiff) {
                answer.add(Arrays.asList(arr[i], arr[i + 1]));
            }
        }

        return answer;   
}