공부하자 동진아

def solution(num):
    answer = 0
    
    while True:
        if num == 1:
            break
            
        if num%2 == 0:
            num = num / 2
            answer += 1
        else:
            num = num * 3 + 1
            answer += 1
        
        if answer >= 500:
            return -1
        
    return answer

def solution(arr):
    answer = []
    
    if len(arr) == 1:
        answer.append(-1)
        arr = answer
    else:
        arr.remove(min(arr))

    return arr

def solution(s):
    answer = []
    n_answer = s.split(" ")
    
    print(n_answer)
    
    for i in n_answer:
        for idx, j in enumerate(list(i)):
            if idx%2 == 0:
                answer.append(j.upper())
            else:
                answer.append(j.lower())
        answer.append(" ")
                
    return "".join(answer)[:-1]

def solution(s):
    answer = []
    answer_s = []
    
    for i in list(s):
        answer_s.append(ord(i))
    
    answer_s = sorted(answer_s)
    
    for i in answer_s:
        answer.append(chr(i))
    
    return "".join(answer)[::-1]