|143|[Reorder List](https://leetcode.com/problems/reorder-list/)|[Solution](../master/src/main/java/com/stevesun/solutions/ReorderList.java)| O(n)|O(1) | Medium|

|142|[Linked List Cycle II](https://leetcode.com/problems/linked-list-cycle-ii/)|[Solution](../master/src/main/java/com/stevesun/solutions/LinkedListCycleII.java)| O(n)|O(1) | Medium| Linked List

|141|[Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/)|[Solution](../master/src/main/java/com/stevesun/solutions/_141.java)| O(n)|O(1) | Easy| Linked List

|139|[Word Break](https://leetcode.com/problems/word-break/)|[Solution](../master/src/main/java/com/stevesun/solutions/WordBreak.java)| O(n^2)|O(n) | Medium| DP

|138|[Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer/)|[Solution](../master/src/main/java/com/stevesun/solutions/_138.java)| O(n)|O(n) | Medium| LinkedList, HashMap

|137|[Single Number II](https://leetcode.com/problems/single-number-ii/)|[Solution](../master/src/main/java/com/stevesun/solutions/SingleNumberII.java)| O(n)|O(n) | Medium|

public List<String> wordBreak(String s, Set<String> wordDict) {

return dfs(s, wordDict, new HashMap<String, ArrayList<String>>());

}

temp2.add("");

System.out.println(temp2);

Set<String> wordDict = new HashSet();

wordDict.add("cat");

wordDict.add("cats");