Leetcode solutions

#	Title	Solution	Difficulty
1	Two Sum	C++	Easy
17	Letter Combinations of a Phone Number	C++	Medium
20	Valid Parentheses	C++	Easy
21	Merge Two Sorted Lists	C++	Easy
22	Generate Parentheses	C++	Medium
24	Swap Nodes in Pairs	C++	Medium
30	Substring with Concatenation of All Words	C++	Hard
36	Valid Sudoku	C++	Medium
41	First Missing Positive	C++	Hard
53	Maximum Subarray	C++	Medium
54	Spiral Matrix	C++	Medium
59	Spiral Matrix II	C++	Medium
62	Unique Paths	C++	Medium
66	Plus One	C++	Easy
70	Climbing Stairs	C++	Easy
73	Set Matrix Zeroes	C++	Medium
75	Sort Colors	C++	Medium
94	Binary Tree Inorder Traversal	C++	Easy
98	Validate Binary Search Tree	C++	Medium
101	Symmetric Tree	C++	Easy
102	Binary Tree Level Order Traversal	C++	Medium
104	Maximum Depth of Binary Tree	C++	Easy
105	Construct Binary Tree from Preorder and Inorder Traversal	C++	Medium
106	Construct Binary Tree from Inorder and Postorder Traversal	C++	Medium
108	Convert Sorted Array to Binary Search Tree	C++	Easy
110	Balanced Binary Tree	C++	Easy
112	Path Sum	C++	Easy
116	Populating Next Right Pointers in Each Node	C++	Medium
119	Pascal's Triangle II	C++	Easy
121	Best Time to Buy and Sell Stock	C++	Easy
122	Best Time to Buy and Sell Stock II	C++	Medium
125	Valid Palindrome	C++	Easy
128	Longest Consecutive Sequence	C++	Medium
130	Surrounded Regions	C++	Medium
134	Gas Station	C++	Medium
137	Single Number II	C++	Medium
138	Copy List with Random Pointer	C++	Medium
142	Linked List Cycle II	C++	Medium
144	Binary Tree Preorder Traversal	C++	Easy
145	Binary Tree Postorder Traversal	C++	Easy
148	Sort List	C++	Medium
150	Evaluate Reverse Polish Notation	C++	Medium
152	Maximum Product Subarray	C++	Medium
162	Find Peak Element	C++	Medium
172	Factorial Trailing Zeroes	C++	Medium
179	Largest Number	C++	Medium
189	Rotate Array	C++	Medium
198	House Robber	C++	Medium
200	Number of Islands	C++	Medium
204	Count Primes	C++	Medium
205	Isomorphic Strings	C++	Easy
206	Reverse Linked List	C++	Easy
209	Minimum Size Subarray Sum	C++	Medium
226	Invert Binary Tree	C++	Easy
228	Summary Ranges	C++	Easy
235	Lowest Common Ancestor of a Binary Search Tree	C++	Medium
278	First Bad Version	C++	Easy
299	Bulls and Cows	C++	Medium
338	Counting Bits	C++	Easy
347	Top K Frequent Elements	C++	Medium
384	Shuffle an Array	C++	Medium
392	Is Subsequence	C++	Easy
399	Evaluate Division	C++	Medium
409	Longest Palindrome	C++	Easy
424	Longest Repeating Character Replacement	C++	Medium
438	Find All Anagrams in a String	C++	Medium
454	4Sum II	C++	Medium
509	Fibonacci Number	C++	Easy
530	Minimum Absolute Difference in BST	C++	Easy
535	Encode and Decode TinyURL	C++	Medium
547	umber of Provinces	C++	Medium
559	Maximum Depth of N-ary Tree	C++	Easy
589	N-ary Tree Preorder Traversal	C++	Easy
590	N-ary Tree Postorder Traversal	C++	Easy
606	Construct String from Binary Tree	C++	Easy
617	Merge Two Binary Trees	C++	Easy
637	Average of Levels in Binary Tree	C++	Easy
649	Dota2 Senate	C++	Medium
692	Top K Frequent Words	C++	Medium
700	Search in a Binary Search Tree	C++	Easy
703	Kth Largest Element in a Stream	C++	Easy
704	Binary Search	C++	Easy
724	Find Pivot Index	C++	Easy
733	Flood Fill	C++	Easy
746	Min Cost Climbing Stairs	C++	Easy
784	Letter Case Permutation	C++	Medium
785	Is Graph Bipartite?	C++	Medium
779	K-th Symbol in Grammar	C++	Medium
844	Backspace String Compare	C++	Easy
876	Middle of the Linked List	C++	Medium
872	Leaf-Similar Trees	C++	Easy
897	Increasing Order Search Tree	C++	Easy
938	Range Sum of BST	C++	Easy
949	Largest Time for Given Digits	C++	Easy
1022	Sum of Root To Leaf Binary Numbers	C++	Easy
1025	Divisor Game	C++	Easy
1035	Uncrossed Lines	C++	Medium
1046	Last Stone Weight	C++	Easy
1091	Shortest Path in Binary Matrix	C++	Medium
1137	N-th Tribonacci Number	C++	Easy
1146	Snapshot Array	C++	Medium
1161	Maximum Level Sum of a Binary Tree	C++	Medium
1232	Check If It Is a Straight Line	C++	Easy
1302	Deepest Leaves Sum	C++	Medium
1318	Minimum Flips to Make a OR b Equal to c	C++	Medium
1343	Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold	C++	Medium
1365	How Many Numbers Are Smaller Than the Current Number	C++	Easy
1376	Time Needed to Inform All Employees	C++	Medium
1379	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	C++	Easy
1456	Maximum Number of Vowels in a Substring of Given Length	C++	Medium
1464	Maximum Product of Two Elements in an Array	C++	Medium
1480	Running Sum of 1d Array	C++	Easy
1491	Average Salary Excluding the Minimum and Maximum Salary	C++	Easy
1492	The kth Factor of n	C++	Medium
1493	Longest Subarray of 1's After Deleting One Element	C++	Medium
1498	Number of Subsequences That Satisfy the Given Sum Condition	C++	Medium
1509	Minimum Difference Between Largest and Smallest Value in Three Moves	C++	Medium
1512	Number of Good Pairs	C++	Easy
1525	Number of Good Ways to Split a String	C++	Medium
1557	Minimum Number of Vertices to Reach All Nodes	C++	Medium
1572	Matrix Diagonal Sum	C++	Easy
1647	Minimum Deletions to Make Character Frequencies Unique	C++	Medium
1802	Maximum Value at a Given Index in a Bounded Array	C++	Medium
1964	Find the Longest Valid Obstacle Course at Each Position	C++	Hard
1970	Last Day Where You Can Still Cross	C++	Hard
2024	Maximize the Confusion of an Exam	C++	Medium
2101	Detonate the Maximum Bombs	C++	Medium
2109	Adding Spaces to a String	C++	Medium
2130	Maximum Twin Sum of a Linked List	C++	Medium
2140	Solving Questions With Brainpower	C++	Medium
2215	Find the Difference of Two Arrays	C++	Easy
2305	Fair Distribution of Cookies	C++	Medium
2331	Evaluate Boolean Binary Tree	C++	Easy
2352	Equal Row and Column Pairs	C++	Medium
2405	Optimal Partition of String	C++	Medium
2462	Total Cost to Hire K Workers	C++	Medium
2466	Count Ways To Build Good Strings	C++	Medium
2542	Maximum Subsequence Score	C++	Medium
2551	Put Marbles in Bags	C++	Medium
2610	Convert an Array Into a 2D Array With Conditions	C++	Medium
2734	Lexicographically Smallest String After Substring Operation	C++	Medium