Word Break II

Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word.

Return all such possible sentences.

For example, given
s = "catsanddog",
dict = ["cat", "cats", "and", "sand", "dog"].

A solution is ["cats and dog", "cat sand dog"].

参考：http://www.tuicool.com/articles/ZVJJRrF

 1 import java.util.ArrayList;
 2 import java.util.LinkedList;
 3 import java.util.List;
 4 import java.util.Set;
 5 
 6 public class Solution {
 7     public List<String> wordBreak(String s, Set<String> dict) {
 8         List<String> dp[] = new ArrayList[s.length() + 1];
 9         dp[0] = new ArrayList<String>();
10         
11         for(int i = 0; i < s.length(); i++){
12             if(dp[i] == null)
13                 continue;
14             for(String word : dict){
15                 int length = word.length();
16                 int end = i + length;
17                 if(end > s.length())
18                     continue;
19                 if(s.substring(i, end).equals(word)){
20                     if(dp[end] == null)
21                         dp[end] = new ArrayList<String>();
22                     dp[end].add(word);
23                 }//if
24             }//for
25         }//for
26         List<String> result = new LinkedList<String>();
27         if(dp[s.length()] == null)
28             return result;
29         List<String> temp = new ArrayList<String>();
30         
31         dfsStringList(dp, result, s.length(), temp);
32         
33         return result;
34     }
35     
36     private void dfsStringList(List<String> dp[], List<String> ans, 
37             int end, List<String> temp){
38         if(end <= 0){
39             String strAns = temp.get(temp.size() - 1);
40             for(int i = temp.size() - 2; i >= 0; i--)
41                 strAns += " " + temp.get(i);
42             ans.add(strAns);
43             return;
44         }//if
45         for(String str : dp[end]){
46             temp.add(str);
47             dfsStringList(dp, ans, end - str.length(), temp);
48             temp.remove(temp.size() - 1);
49         }
50     }
51 }