"""
139. Word Break
Medium

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

https://leetcode.com/problems/word-break/submissions/
"""
class Solution:
    def wordBreak(self, s: str, wordDict: List[str]) -> bool:
        def btrack(x):
            for w in wordDict:
                if len(x) < len(w):
                    continue
                elif x == w:
                    return True
                elif x[:len(w)] == w:
                    if btrack(x[len(w):]):
                        return True
        return bool(btrack(s))
