5452. Can Make Arithmetic Progression From Sequence

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

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给一个数组，问能否通过排列组合让这个数组变成等差数列。

直接排序，看看是否是等差数列即可：

class Solution {
public:
	bool canMakeArithmeticProgression(vector<int>& arr) {
		sort(arr.begin(), arr.end());
		int diff = arr[1] - arr[0];
		for (int i = 2; i < arr.size(); ++i) {
			if (arr[i] - arr[i - 1] != diff)return false;
		}
		return true;
	}
};

本代码提交AC。