Word Break

Problem Statement

Given a string s and a dictionary of strings wordDict, return true if s can be segmented into a space-separated sequence of one or more dictionary words.

Note that the same word in the dictionary may be reused multiple times in the segmentation.

Leetcode link

Examples

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

Constraints

1 <= s.length <= 300
1 <= wordDict.length <= 1000
1 <= wordDict[i].length <= 20
s and wordDict[i] consist of only lowercase English letters.
All the strings of wordDict are unique.

Code

Python3 Code

class Solution:
    def wordBreak(self, s: str, wordDict: List[str]) -> bool:
        word_dict=set(wordDict)
        flag=None
        word=''
        cache=[0]
        for i in range(len(s)):
            word+=s[i]
            for j in cache:
                flag=False
                if word[j:] in word_dict:
                    flag=True
                    cache.append(i+1)
                    break
        return flag