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Word Break

Detailed guide and Python implementation for the 'Word Break' problem.

Problem Statement

Medium

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.

Write a function wordBreak(s: str, wordDict: List[str]) -> bool.

Constraints
  • 1 <= len(s) <= 300
  • 1 <= len(wordDict) <= 1000
  • 1 <= len(wordDict[i]) <= 20
  • s and wordDict[i] consist of only lowercase English letters
  • All the strings of wordDict are unique

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".

Example 3
Input
s = "catsandog", wordDict = ["cats","dog","sand","and","cat"]
Output
False
Explanation

No valid segmentation exists.

Need a Hint?
Consider using 1D DP-specific data structures like sets or heaps.
Edge Cases to Watch
  • Empty input structures
  • Single element inputs
  • Large numerical bounds

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