lintcode_79最长公共字串

class Solution:
    """
    @param: A: A string
    @param: B: A string
    @return: the length of the longest common substring.
    """
    def longestCommonSubstring(self, A, B):
        # write your code here
        if not A:
            return 0
        result = -1
        for i in range(len(B)):
            for j in range(i,len(B)+1):
                result = max(j-i,result) if A.find(B[i:j])!=-1 else result
        return result