lc1502. Can Make Arithmetic Progression From Sequence

1502. Can Make Arithmetic Progression From Sequence Easy

78

6

Add to List

Share 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.

思路： 1.排序 2.遍历，如果a[i]*2!=a[i-1]+a[i+1],break，返回false

代码：python3

#1502
class Solution:
    def canMakeArithmeticProgression(self, arr):
        arr.sort()
        res=True
        for i in range(1,len(arr)-1):
            if arr[i]*2!=arr[i-1]+arr[i+1]:
                res=False
                break
        return res
if __name__ == '__main__':
    print(Solution().canMakeArithmeticProgression([1,3,5,7,11,9]))        

时间复杂度：O(mlogm) 空间复杂度：O(logm)