All problems
MediumDp

Word Break

amazongooglemetamicrosoftbloombergappleuber

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.

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
Explanation: No valid segmentation exists for "catsandog".

Examples

Example 1

Input: s = "leetcode", wordDict = ["leet","code"]

Output: true

Explanation: "leetcode" can be split as "leet" + "code", both of which are in the dictionary.

Example 2

Input: s = "applepenapple", wordDict = ["apple","pen"]

Output: true

Explanation: "applepenapple" can be split as "apple" + "pen" + "apple". Dictionary words can be reused.

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

Optimal Complexity

Time

O(n^2 * m)

Space

O(n)

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