# 139 Word Break – Medium

### 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".

### Thoughts:

We could use a dynamic programing approach for this problem.

A[i] stands for for the substring [0, i], if it is a valid word break string.

A[i] = A[j] && dict.contains(substring(j+1, i))

### Solutions:

``````public class Solution {
public boolean wordBreak(String s, Set<String> wordDict){
if (s == null || s.length() == 0) {
return false;
}
boolean[] canBreak = new boolean[s.length()];
for (int i = 0; i < s.length(); i ++) {
if (wordDict.contains(s.substring(0, i + 1))) {
canBreak[i] = true;
continue;
}
for (int j = 0; j < i; j ++) {
if (canBreak[j] && wordDict.contains(s.substring(j + 1, i + 1))){
canBreak[i] = true;
break;
}
}
}
return canBreak[canBreak.length - 1];
}
}
``````