- (378) Kth Smallest Element in a Sorted Matrix
- (Lintcode 465) Kth Smallest Sum in Two Sorted Arrays
- (3) Longest Substring Without Repeating Characters
- (209) Minimum Size Subarray Sum
- (340) Longest Substring with At Most K Distinct Characters
- (261) Graph Valid Tree
- (305) Number of Island II
- (Lintcode 590) Connecting Graph II
- (Lintcode 629) Minimum Spanning Tree
- (721) Accounts Merge
- (208) Implement Trie (Prefix Tree)
- (211) Add and Search Word - Data structure design
- (212) Word Search II
- (Lintcode 138) Subarray Sum
- (Lintcode 405) Submatrix Sum
- (155) Min Stack
- (394) Decode String
- (654) Maximum Binary Tree
- (Lintcode 22) Flatten List
- (Lintcode 402) Continuous Subarray Sum
- (341) Flatten Nested List Iterator
- (42) Trapping Rain Water
- (84) Largest Rectangle in Histogram
- (85) Maximal Rectangle
- (295) Find Median from Data Stream
- (480) Sliding Window Median
- (407) Trapping Rain Water II
- (253) Meeting Rooms II
- (Lintcode 391) Number of Airplanes in the Skyline
- (29) Divide Two Integers
- (69) Sqrt(x)
- (287) Find the Duplicate Number
- (644) Maximum Average Subarray II
- (Lintcode 183) Wood Cut
- (Lintcode 437) Copy Books
- (Lintcode 586) Sqrt(x) II
- (239) Sliding Window Maximum
- (346) Moving Average from Data Stream
- (198) House Robber