[Python] Lv1 숫자 짝꿍

 

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from collections import Counter

def solution(X, Y):
	count_x = Counter(X)
    count_y = Counter(Y)
    
    common_digit = set(X) & set(Y)
    
    result = []
    
    for digit in common_digit:
    	min_count = min(count_x[digit], count_y[digit])
        result.extend([digit] * min_count)
        
    result.sort(reverse=True)
    
    if len(result) == 0:
    	return '-1'
    if result[0] == '0':
    	return '0'
        
    return ''.join(result)