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
# TLE solution class Solution: def helper(self, s): if not s: return True return any(self.helper(s[len(word):]) for word in self.wordDict if s.startswith(word)) def wordBreak(self, s: str, wordDict: List[str]) -> bool: self.wordDict = wordDict return self.helper(s)
# Basic DP class Solution: def wordBreak(self, s: str, wordDict: List[str]) -> bool: dp = [False] * len(s) for i in range(len(s)): for word in wordDict: if s[:i+1].endswith(word) and (dp[i-len(word)] or i-len(word) == -1): dp[i] = True return dp[-1]
# Advanced DP class Solution: def wordBreak(self, s: str, wordDict: List[str]) -> bool: dp = [True] for i in range(1, len(s)+1): dp += any(dp[j] and s[j:i] in wordDict for j in range(i)), return dp[-1]