题解 | #查找两个字符串a,b中的最长公共子串#

def child(x):           ####求个最长子串
    l = []
    for i in range(len(x)):
        for j in range(i+1,len(x)+1):
            l.append(x[i:j])
    return l

while True:
    try:
        a = str(input())
        b = str(input())
        ll = []                  ####小的子串in大的保存
        if len(a) > len(b):
            s1 = b
            s2 = a
        else:
            s2 = b
            s1 = a
        for i in child(s1):
            if i in s2:
                ll.append(i)
        print(sorted(ll,key=len,reverse=True)[0])   ###按字符串长度排序，长度相同，默认取第一个
    except:
        break