140. 单词拆分 II

1. 题目链接

2. 解题思路：和139题类似，只不过要把所有的结果存起来而已

3. 代码

   class Solution:
    
       def check(self, s: str, i: int, s2: str) -> int:
           if i + len(s2) > len(s):
               return -1
           for ch in s2:
               if ch != s[i]:
                   return -1
               i += 1
           return i
    
       # 现在在凑s[index...]，能凑出来吗？
       def process(self, s: str, index: int, wordDict: List[str], ans: List[str], res: str) -> None:
           if index == len(s):
               ans.append(res)
               return 
           # 用哪个字符来凑？
           for str1 in wordDict:
               next_index = self.check(s, index, str1)
               if next_index != -1:
                   add_count = 0
                   if len(res) == 0:
                       res += str1
                       add_count = len(str1)
                   else:
                       res += ' '
                       res += str1
                       add_count = len(str1) + 1
                   self.process(s, next_index, wordDict, ans, res)
                   # 恢复现场
                   res = res[:-add_count]
    
       def wordBreak(self, s: str, wordDict: List[str]) -> List[str]:
           ans = []
           res = ""
           self.process(s, 0, wordDict, ans, res)
           return ans