Trapping Rain Water
Length of Last Word
Valid Parentheses
Subsets
Valid Sudoku
jump game
permutation II
Longest Consecutive Sequence
subset II
Convert Sorted List to Binary Search Tree
Search for a Range
3Sum Closest
pow x n
Flatten_Binary_Tree_to_Linked_List
Reverse_Linked_List_II
Longest Common Prefix
Count and Say
Triangle
Binary Tree Zigzag Level Order Traversal
Combination Sum