[LeetCode] Word Break

Problem:

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.

For example, given
s = "leetcode",
dict = ["leet", "code"].

Return true because "leetcode" can be segmented as "leet code".

Solution:O(n*n)

public class Solution {
    public boolean wordBreak(String s, Set<String> dict){
         if (s==null || dict==null){
             return false;
         }
         
         if (dict.size()==0) 
             return s.length()==0;
         
         boolean[] DP=new boolean[s.length()+1];
         DP[0]=true;
         
         for (int i=1; i<=s.length(); i++){
             for (int k=0; k<i; k++){
                 if (DP[k]&&dict.contains(s.substring(k, i))){
                     DP[i]=true;
                     break;
                 }
             }
         }
         
         return DP[s.length()];
     }
}