1306. Minimum Absolute Difference

• Difficulty: Easy

• Topics: Array

• Similar Questions:

Problem:

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

Solutions:

class Solution {
public:
    vector<vector<int>> minimumAbsDifference(vector<int>& arr) {
        int n = arr.size();
        if (n <= 1) return {};
        sort(arr.begin(), arr.end());

        vector<vector<int>> ret;
        int minDiff = INT_MAX;

        for (int i = 1; i < n; ++i) {
            if (abs(arr[i] - arr[i-1]) == minDiff) {
                ret.push_back({arr[i-1], arr[i]});
            } else if (abs(arr[i] - arr[i-1]) < minDiff) {
                minDiff = abs(arr[i] - arr[i-1]);
                ret = {{arr[i-1], arr[i]}};
            }
        }

        return ret;
    }
};