LeetCode 139, Medium. Topics: Array, Hash Table, String, Dynamic Programming, Trie, Memoization. View on LeetCode.
Generate this problem as a practice environment: tested reference solution, 15 parametrized pytest cases, and a playground notebook:
Problem
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.
Examples
Explanation: Return true because “leetcode” can be segmented as “leet code”.
Explanation: Return true because “applepenapple” can be segmented as “apple pen apple”.
Note that you are allowed to reuse a dictionary word.
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.
Solution
Reference implementation from solution.py on GitHub, full suite in test_solution.py:
Complexity
Grind 75, Grind, Blind 75, NeetCode 150, NeetCode 250, NeetCode All, AlgoMaster 75. Last modified on September 7, 2026