큰 수 만들기

def solution(number, k):
    collected = []
    for i,num in enumerate(number) : #i=인덱스, num=값

        while len(collected) >0 and collected[-1] < num and k>0 :
            collected.pop()
            k-=1
        if k == 0 :
            collected += list(number[i:])
            break
        collected.append(num)

    collected = collected[:-k] if k>0 else collected
    answer = ''.join(collected)
    return answer