Add reverse(ListNode pre, ListNode next) to reverse a linked list
Add reverseNodesInKGroup
Add Valid Parentheses
Add Swap Nodes in Pairs
Add Generate Parentheses
Reviewed Anagrams and move it to the package of permutation
Move ClimbingStairs to the package of dp
Refactor the packages
Refactor the packages
add Remove the Nth Node from End of List