n = int(input()) a = list(map(int, input().split())) sum_angles = sum(a) expected_sum = (n - 2) * 180 if sum_angles == expected_sum and all(1 <= angle < 180 for angle in a): print("Yes") else: print("No")

首先根据初二上的数学知识，nnn 边形内角和为 (n−2)180°(n-2)180\degree(n−2)180°，为 180°180\degree180° 的倍数，所以累加判断即可。 Code: