No1502.can-make-arithmetic-progression-from-sequence.cs

/*
 * Difficulty:
 * Easy
 *
 * Desc:
 * Given an array of numbers arr. A sequence of numbers is called an arithmetic progression if the difference between any two consecutive elements is the same.
 * Return true if the array can be rearranged to form an arithmetic progression, otherwise, return false.
 *
 * Example 1:
 * Input: arr = [3,5,1]
 * Output: true
 * Explanation:
 * We can reorder the elements as [1,3,5] or [5,3,1] with differences 2 and -2 respectively, between each consecutive elements.
 *
 * Example 2:
 * Input: arr = [1,2,4]
 * Output: false
 * Explanation: There is no way to reorder the elements to obtain an arithmetic progression.
 *
 * Constraints:
 * 2 <= arr.length <= 1000
 * -10^6 <= arr[i] <= 10^6
*/

public class Solution {
    public bool CanMakeArithmeticProgression(int[] arr) {
        Array.Sort(arr);
        for (int i = 1; i < arr.Length - 1; i += 1) {
            if (arr[i] - arr[i - 1] != arr[i + 1] - arr[i]) return false;
        }
        return true;
    }
}