Leetcode Word Break

public class Solution {
public boolean wordBreak(String s, Set<String> dict) {
if (s == null)
return false;
boolean flag[] = new boolean[s.length() + 1];
flag[0] = true;
for (int i = 1; i <= s.length(); i++) {
for (String temp : dict) {
int length = temp.length();
if (length > i) {
flag[i] = false;
continue;
}
if (s.substring(i - length, i).equals(temp) && flag[i - length]) {
flag[i] = true;
break;
}
flag[i] = false;
}
}
return flag[s.length()];
}
}