백준 1065 - 한수 (파이썬)

Answer

n = int(input())
answer = n

def is_arithmetic_sequence(n):
    temp = str(n)
    
    if int(temp[1]) * 2 == int(temp[0]) + int(temp[2]):
        return 1
        
    return 0
            
if n >= 100:
    answer = 99
    for i in range(100, n + 1):
        answer += is_arithmetic_sequence(i)

print(answer)