视频分享：一道回文串的题目：什么情况下用递归，如何用递归 #LeetCode #数据结构与算法

# 示例
输入: "aab"
输出:
[
  ["aa","b"],
  ["a","a","b"]
]

class Solution:
    def partition(self, s: str) -> List[List[str]]:
        def ispartition(sub):
            for i in range((len(sub) + 1) // 2):
                if sub[i] != sub[len(sub) - i - 1]:
                    return False
            return True

        rts = []
        def bfs(father, ss):
            if len(ss) == 0:
                rts.append(father)
                return
            for i in range(len(ss)):
                tmp = father.copy()
                upper = ss[:(i+1)]
                lower = ss[(i+1):]
                if ispartition(upper):
                    tmp.append(upper)
                    bfs(tmp, lower)
            return 0
        
        bfs([], s)
        return rts