136. 分割回文串

class Solution:
    """
    @param: s: A string
    @return: A list of lists of string
    """
    def partition(self, ss):
        if not ss:return None

        #初始条件
        dp = [[] for _ in range(len(ss))]
        dp[0] = [[ss[0]]]

        #计算顺序
        for i in range(1,len(ss)):
            for j in range(i+1):
                s = ss[j:i] + ss[i]
        
                
                #边界情况
                if s == s[::-1]:
                    if j == 0:
                        dp[i].append([ss[:i+1]])
                        continue

                    for dic in dp[j-1]:
                        append_dic = dic + [s]
                        dp[i].append(append_dic)
        return dp[-1]