diff --git a/problems/0139.单词拆分.md b/problems/0139.单词拆分.md index a3d59ec7..5ad0fcb0 100644 --- a/problems/0139.单词拆分.md +++ b/problems/0139.单词拆分.md @@ -394,7 +394,28 @@ class Solution: dp[j] = dp[j] or (dp[j - len(word)] and word == s[j - len(word):j]) return dp[len(s)] ``` +DP(剪枝) +```python +class Solution(object): + def wordBreak(self, s, wordDict): + + # 先对单词按长度排序 + wordDict.sort(key=lambda x: len(x)) + n = len(s) + dp = [False] * (n + 1) + dp[0] = True + # 遍历背包 + for i in range(1, n + 1): + # 遍历单词 + for word in wordDict: + # 简单的 “剪枝” + if len(word) > i: + break + dp[i] = dp[i] or (dp[i - len(word)] and s[i - len(word): i] == word) + return dp[-1] + +``` ### Go: