Day 1: Invert Binary Tree
Day 2: Delete Node in a Linked List
Day 3: Two City Scheduling
Day 4: Reverse String
Day 5: Random pick with weight
Day 6: Queue Construction by Height
Day 7: Coin Change 2
Day 8: Power of Two
Day 9: Is Subsequence
Day 10: Search Insert Position
Day 11: Sort Colors
Day 12: Insert Delete GetRandom O(1)
Day 13: Largest Divisible Subset
Day 14: Cheapest Flights Within K Stops
Day 15: Search in a Binary Search Tree
Day 16: Validate IP Address
Day 17: Surrounded Regions
Day 18: H-Index II
Day 19: Longest Duplicate Substring
Day 20: Permutation Sequence
Day 21: Dungeon Game
Day 22: Single Number II
Day 23: Count Complete Tree Nodes
Day 24: Unique Binary Search Trees
Day 25: Find the Duplicate Number
Day 26: Sum Root to Leaf Numbers
Day 27: Perfect Squares
Day 28: Reconstruct Itinerary
Day 29: Unique Paths
Day 30:Word Search 2
#Finally Finish :) :)
