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wordBreakII.java
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wordBreakII.java
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import java.awt.List;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.ArrayList;
public class wordBreakII {
//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.
public void dfs(ArrayList<String>[] dp,int end,ArrayList<String> result, ArrayList<String> tmp){
if(end <= 0){
String path = tmp.get(tmp.size()-1);
for(int i=tmp.size()-2; i>=0; i--){
path += " " + tmp.get(i) ;
}
result.add(path);
return;
}
for(String str : dp[end]){
tmp.add(str);
dfs(dp, end-str.length(), result, tmp);
tmp.remove(tmp.size()-1);
}
}
public ArrayList<String> wordBreak(String s, ArrayList<String> dict) {
//create an array of ArrayList<String>
Set<String> foo = new HashSet<>(dict);
ArrayList<String> dp[] = new ArrayList[s.length()+1];
dp[0] = new ArrayList<String>();
for(int i=0; i<s.length(); i++){
if( dp[i] == null )
continue;
for(String word:foo){
int len = word.length();
int end = i+len;
if(end > s.length())
continue;
if(s.substring(i,end).equals(word)){
if(dp[end] == null){
dp[end] = new ArrayList<String>();
}
dp[end].add(word);
}
}
}
ArrayList<String> result = new ArrayList<String>();
if(dp[s.length()] == null)
return result;
ArrayList<String> temp = new ArrayList<String>();
dfs(dp, s.length(), result, temp);
Collections.sort(result);
return result;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
ArrayList<String> dict = new ArrayList<>(Arrays.asList("cat","cats","and","sand","dog"));
System.out.println(new wordBreakII().wordBreak("catsanddog", dict));
}
}