符合条件的代码怎样编写？

def prefix(s1,s2):
    s=''
    for i in range(max(len(s1),len(s2))):
        if s1[i] == s2[i]:
            s+=s1[i]
        else:
            break
    return s

s1=input()
s2=input()
print(prefix(s1,s2))

https://leetcode-cn.com/problems/longest-common-prefix/solution/zui-chang-gong-gong-qian-zhui-by-leetcode-solution/

def func(s1,s2):
   if len(s1)>len(s2):
        k=s1
        s1=s2
        s2=k
   print s1
   print s2
   for i in range(len(s1),0,-1):
       q=''
       for j in range(0,len(s1)-i+1):

           t=s1[j:j+i]
           print j,i,t
           if s2.find(t) != -1:
               q=q+t+' '
       if q != '':
           print q
           break