[파이썬] 프로그래머스 숫자 짝꿍

 
def solution(X, Y):
    answer = [ ]
 
    a = list(map(int,X))
    b = list(map(int,Y))
 
    n = [0,0,0,0,0,0,0,0,0,0]
    m = [0,0,0,0,0,0,0,0,0,0]
 
 
    for i in range(0,len(a)):
        n[a[i]]+=1
 
    for i in range(0,len(b)):
        m[b[i]]+=1
 
 
    k = [0,0,0,0,0,0,0,0,0,0]
 
    for i in range(0,10):
        k[i] = abs(max(n[i],m[i])-n[i]-m[i])
 
 
 
    for i in range(0,10):
        for j in range(0,k[i]):
            answer.append(i)
 
 
    if len(answer)==0:
        return '-1'
 
    answer.reverse()
    if answer[0]==0:
        return "0"
    return "".join(map(str,answer))