The topic is from LeetCode
139. Word Split
Other solutions or source code can be accessed: tongji4m3
description
Given a non-empty string s and a list wordDict containing non-empty words, determine whether s can be split by spaces into one or more words that appear in the dictionary.
Description:
Words in the dictionary can be reused when splitting.
You can assume that there are no repeated words in the dictionary.
Example 1:
输入: s = "leetcode", wordDict = ["leet", "code"]
输出: true
解释: 返回 true 因为 "leetcode" 可以被拆分成 "leet code"。
Example 2:
输入: s = "applepenapple", wordDict = ["apple", "pen"]
输出: true
解释: 返回 true 因为 "applepenapple" 可以被拆分成 "apple pen apple"。
注意你可以重复使用字典中的单词。
Example 3:
输入: s = "catsandog", wordDict = ["cats", "dog", "sand", "and", "cat"]
输出: false
Ideas
动态规划
dp[i]代表s.substring(0,i)能否被表示
dp[0]=true
return dp[s.length()]
dp[i]=
for j in [0,i):
只要包含了一个(前一部分存在,剩下的那个单词在wordDict中)
Code
public boolean wordBreak(String s, List<String> wordDict)
{
if(s==null || s.length()==0) return false;
boolean[] dp = new boolean[s.length() + 1];
dp[0] = true;
for (int i = 0; i < dp.length; i++)
{
for (int j = 0; j < i; j++)
{
if (dp[j] && wordDict.contains(s.substring(j, i)))
{
dp[i] = true;
break;//look 找到一个即可,不用继续找了
}
}
}
return dp[s.length()];
}