packagemedium;

importclasses.ListNode;

publicclassLinkedListCycleII {

publicListNodedetectCycle(ListNodehead) {

ListNodeslow =head,fast =head;

while (fast !=null &&fast.next !=null) {

slow =slow.next;

fast =fast.next.next;

if (slow ==fast) {

ListNodeslow2 =head;

while (slow2 !=slow) {

slow =slow.next;

slow2 =slow2.next;

}

returnslow;

}

}

returnnull;

}

}

|157|[Read N Characters Given Read4](https://leetcode.com/problems/read-n-characters-given-read4/)|[Solution](../../blob/master/EASY/src/easy/ReadNCharactersGivenRead4.java)| O(n)|O(1)| Easy|

|155|[Min Stack](https://leetcode.com/problems/min-stack/)|[Solution](../../blob/master/EASY/src/easy/MinStack.java)| O(1)|O(n) | Easy| Stack

|151|[Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string/)|[Solution](../../blob/master/MEDIUM/src/medium/ReverseWordsinaString.java)| O(n)|O(n)| Medium|

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

|141|[Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/)|[Solution](../../blob/master/EASY/src/easy/LinkedListCycle.java)| O(n)|O(1) | Easy| Linked List

|140|[Word Break II](https://leetcode.com/problems/word-break-ii/)|[Solution](../../blob/master/HARD/src/hard/WordBreakII.java)| ? |O(n^2) | Hard| Backtracking/DFS

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