[27일차][프로그래머스][12940]같은 숫자는 싫어

def solution(arr):
    check_number = -1
    result = []
    for number in arr:
        if check_number == -1:
            check_number = number
            result.append(number)
            
        if check_number != number:            
            check_number = number
            result.append(number)
            
    return result

def solution(arr):
    check_number = 0
    result = []
    for idx in range(len(arr)):
        if idx == 0:
            check_number = arr[idx]
            result.append(arr[idx])
        else:
            if check_number != arr[idx]:
                check_number = arr[idx]
                result.append(arr[idx])
                
    return result