Solution for Array

#	Name	Difficulty	Tags
1	Two Sum	Easy	Array | Hash Table
4	Median of Two Sorted Arrays	Hard	Array | Binary Search | Divide and Conquer
15	3Sum	Medium	Array | Two Pointers
16	3Sum Closest	Medium	Array | Two Pointers
18	4Sum	Medium	Array | Hash Table | Two Pointers
26	Remove Duplicates from Sorted Array	Easy	Array | Two Pointers
27	Remove Element	Easy	Array | Two Pointers
31	Next Permutation	Medium	Array
33	Search in Rotated Sorted Array	Medium	Array | Binary Search
34	Find First and Last Position of Element in Sorted Array	Medium	Array | Binary Search
35	Search Insert Position	Easy	Array | Binary Search
39	Combination Sum	Medium	Array | Backtracking
40	Combination Sum II	Medium	Array | Backtracking
41	First Missing Positive	Hard	Array
42	Trapping Rain Water	Hard	Array | Two Pointers | Stack
45	Jump Game II	Hard	Array | Greedy
48	Rotate Image	Medium	Array
53	Maximum Subarray	Easy	Array | Divide and Conquer | Dynamic Programming
54	Spiral Matrix	Medium	Array
55	Jump Game	Medium	Array | Greedy
56	Merge Intervals	Medium	Array | Sort
57	Insert Interval	Medium	Array | Sort
59	Spiral Matrix II	Medium	Array
62	Unique Paths	Medium	Array | Dynamic Programming
63	Unique Paths II	Medium	Array | Dynamic Programming
64	Minimum Path Sum	Medium	Array | Dynamic Programming
66	Plus One	Easy	Array
73	Set Matrix Zeroes	Medium	Array
74	Search a 2D Matrix	Medium	Array | Binary Search
75	Sort Colors	Medium	Array | Two Pointers | Sort
78	Subsets	Medium	Array | Backtracking | Bit Manipulation
79	Word Search	Medium	Array | Backtracking
80	Remove Duplicates from Sorted Array II	Medium	Array | Two Pointers
81	Search in Rotated Sorted Array II	Medium	Array | Binary Search
84	Largest Rectangle in Histogram	Hard	Array | Stack
85	Maximal Rectangle	Hard	Array | Hash Table | Dynamic Programming | Stack
88	Merge Sorted Array	Easy	Array | Two Pointers
90	Subsets II	Medium	Array | Backtracking
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	Array | Tree | Depth-first Search
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	Array | Tree | Depth-first Search
118	Pascal's Triangle	Easy	Array
119	Pascal's Triangle II	Easy	Array
120	Triangle	Medium	Array | Dynamic Programming
121	Best Time to Buy and Sell Stock	Easy	Array | Dynamic Programming
122	Best Time to Buy and Sell Stock II	Easy	Array | Greedy
123	Best Time to Buy and Sell Stock III	Hard	Array | Dynamic Programming
126	Word Ladder II	Hard	Array | String | Backtracking | Breadth-first Search
152	Maximum Product Subarray	Medium	Array | Dynamic Programming
1208	Get Equal Substrings Within Budget	Medium	Array | Sliding Window
1266	Minimum Time Visiting All Points	Easy	Array | Geometry
1267	Count Servers that Communicate	Medium	Array | Graph
1275	Find Winner on a Tic Tac Toe Game	Easy	Array
1277	Count Square Submatrices with All Ones	Medium	Array | Dynamic Programming
1295	Find Numbers with Even Number of Digits	Easy	Array
1296	Divide Array in Sets of K Consecutive Numbers	Medium	Array | Greedy
1346	Check If N and Its Double Exist	Easy	Array
1351	Count Negative Numbers in a Sorted Matrix	Easy	Array | Binary Search
1352	Product of the Last K Numbers	Medium	Array | Design
1365	How Many Numbers Are Smaller Than the Current Number	Easy	Array | Hash Table
1366	Rank Teams by Votes	Medium	Array | Sort
1375	Bulb Switcher III	Medium	Array
1380	Lucky Numbers in a Matrix	Easy	Array
1389	Create Target Array in the Given Order	Easy	Array
1748	Sum of Unique Elements	Easy	Array | Hash Table
1758	Minimum Changes To Make Alternating Binary String	Easy	Array | Greedy
1764	Form Array by Concatenating Subarrays of Another Array	Medium	Array | Greedy
1769	Minimum Number of Operations to Move All Balls to Each Box	Medium	Array | Greedy