Given a non-empty string s and a dictionary wordDict containing a list of non-empty words, determine if s can be segmented into a space-separated sequence of one or more dictionary words.
Note:
- The same word in the dictionary may be reused multiple times in the segmentation.
- You may assume the dictionary does not contain duplicate words.
Example 1:
Input: s = "leetcode", wordDict = ["leet", "code"]
Output: true
Explanation: Return true because"leetcode"
can be segmented as"leet code"
.
Example 2:
Input: s = "applepenapple", wordDict = ["apple", "pen"]
Output: true
Explanation: Return true because"
applepenapple"
can be segmented as"
apple pen apple"
.
Note that you are allowed to reuse a dictionary word.
Example 3:
Input: s = "catsandog", wordDict = ["cats", "dog", "sand", "and", "cat"]
Output: false
这道拆分词句问题是看给定的词句能分被拆分成字典里面的内容,这是一道很经典的题目,解法不止一种,考察的范围很广,属于我们必须要熟练掌握的题目。那么先来想 brute force 的解法,就拿例子1来分析,如果字典中只有两个单词,我们怎么去判断,是不是可以将原字符串s分成任意两段,然后再看分成的单词是否在字典中。注意这道题说是单词可以重复使用,所以可以分成任意段,而且字典中的单词可以有很多个,这就增加了题目的难度,很多童鞋就在这里迷失了,毫无头绪。那么,就由博主来给各位指点迷津吧(此处应有掌声