Add 2 new question and refine the answer for C1_66_CircusSorting
1. For C1_66_CircusSorting, it should consider some candidate can't fit
in the team, so using dynamic programing to find the longest increasing
subarray
2. find unique community in 2 dimensional array: C4_68_TwoDimensionUnionFind
3. keep track numbers rank in a streaming of integer: C4_69_TrackNumberRank