Leetcode notes all in one

All the questions resolved can be found below, enjoy!

Bonus: The locked questions in Leetcode are labeled as "locked".

1. Leetcode 23: Merge K Sorted Lists
2. Leetcode 71: Simply Path
3. Leetcode 76: Minimum Window Substring
4. Leetcode 115: Distinct Subsequences
5. Leetcode 133: Clone Graph
6. Leetcode 146: LRU
7. Leetcode 155: Min Stack
8. Leetcode 156: Binary Tree Upside Down
9. Leetcode 157: Read N Characters Given Read4
10. Leetcode 158: Read N Characters Given Read4 II - Call multiple times
11. Leetcode 188: Best Time to Buy and Sell Stock IV
12. Leetcode 239: Sliding Window Maximum
13. Leetcode 241: Different Ways to Add Parentheses
14. Leetcode 248: Strobogrammatic Number III
15. Leetcode 249: Group Shifted String
16. Leetcode 253: Meeting Rooms II
17. Leetcode 257: Binary Tree Paths
18. Leetcode 264: Ugly Number II
19. Leetcode 276: Paint Fence
20. Leetcode 277: Find the Celebrity
21. Leetcode 309: Best Time to Buy and Sell Stock with Cooldown
22. Leetcode 312: Burst Balloons
23. Leetcode 316: Remove Duplicate Letters
24. Leetcode 321: Create Maximum Number
25. Leetcode 325: Maximum Size Subarray Sum Equals K
26. Leetcode 335: Self-Crossing
27. Leetcode 341: Flatten Nested List Iterator
28. Leetcode 358: Rearrange String K Distance Apart
29. Leetcode 380: Insert Delete GetRandom O(1)
30. Leetcode 381: Insert Delete GetRandom O(1) - Duplicates Allowed
31. Leetcode 392: Is Subsequence
32. Leetcode  395: Longest Substring with At Least K Repeating Characters
33. Leetcode 416: Partition Equal Subset Sum
34. Leetcode 421: Maximum XOR of Two Numbers in an Array
35. Leetcode 430: Flatten a Multilevel Doubly Linked List
36. Leetcode 432: All O'one Data Structure
37. Leetcode 460: LFU Cache
38. Leetcode 474: Ones and Zeroes
39. Leetcode 478: Generate Random Point in a Circle
40. Leetcode 480: Sliding Window Medians
41. Leetcode 508: Most Frequent Subtree Sum
42. Leetcode 514: Freedom Trail
43. Leetcode 525: Contiguous Array
44. Leetcode 526: Beautiful Arrangement
45. Leetcode 562: Longest Line of Consecutive One in Matrix
46. Leetcode 621: Task Scheduler
47. Leetcode 622: Design Circular Queue
48. Leetcode 629: K Pairs Inverse Array
49. Leetcode 630: Course Schedule III
50. Leetcode 638: Shopping Offers
51. Leetcode 641: Design Circular Deque
52. Leetcode 647: Palindromic Substrings
53. Leetcode 650: 2 Keys Keyboard
54. Leetcode 651: 4 Keys Keyboard
55. Leetcode 673: Number of the Longest Increasing Subsequence
56. Leetcode 679: 24 Game
57. Leetcode 698: Partition to K Equal Sum Subsets
58. Leetcode 727: Minimum Window Subsequence
59. Leetcode 730: Counting Different Palindromic Subsequences
60. Leetcode 756: Pyramid Transition Matrix
61. Leetcode 778: Swim in Rising Water
62. Leetcode 781: Rabbits in the Forest
63. Leetcode 792: Number of Matching Subsequences
64. Leetcode 801: Minimum Swaps to Make Sequences Increasing
65. Leetcode 813: Largest Sum of Averages
66. Leetcode 828: Unique Letter String
67. Leetcode 839: Similar String Groups
68. Leetcode 850: Rectangle Area II
69. Leetcode 872: Making a Large Island
70. Leetcode 874: Walking Robot Simulation
71. Leetcode 907: Sum of Subarray Minimums
72. Leetcode 910: Smallest Range II
73. Leetcode 912: Best Meeting Point
74. Leetcode 920: Number of Music Playlists
75. Leetcode 947: Most Stones Removed With Same Rows or Column
76. Leetcode 950: Reveal Cards In Increasing Order
77. Leetcode 952: Largest Component Size by Common Factor
78. Leetcode 970: Powerful Integer
79. Leetcode 979: Distribute Coins in Binary Tree
80. Leetcode 981: Time Based Key-Value Store
81. Leetcode 992: Subarrays with K Different Integers
82. Leetcode 1055: Shortest Way to Form String
83. Leetcode 1057: Campus Bikes
84. Leetcode 1066: Campus Bikes II
85. Leetcode 1072: Flip Columns to Maximum Number of Equal Rows 
86. Leetcode 1081: Smallest Subsequence with Distinct Characters
87. Leetcode 1088: Confusing Number II
88. Leetcode 1104: Path In ZigZag Labelled Binary Tree
89. Leetcode 1135: Connecting Cities With Minimum Cost
90. Leetcode 1140: Stone Game II
91. Leetcode 1142: Flowers Planting With No Adjacent
92. Leetcode 1144: Decrease Elements To Make Array Zigzag
93. Leetcode 1145: Binary Tree Coloring Game
94. Leetcode 1146: Snapshot Array
95. Leetcode 1147: Longest Chunked Palindrome Decomposition
96. Leetcode 1152: Analyze User Website Visit Pattern
97. Leetcode 1153: String Transforms To Another String
98. Leetcode 1167: Minimum Cost to Connect Sticks
99. Leetcode 1168: Optimize Water Distribution in a Village
100. Leetcode 1178: Number of Valid Words for Each Puzzle
101. Leetcode 1183: Maximum Number of Ones
102. Leetcode 1186: Maximum Subarray Sum with One Deletion
103. Leetcode 1187: Make Array Strictly Increasing
104. Leetcode 1199: Minimum Time to Build Blocks
105. Leetcode 1202: Smallest Strings with Swaps
106. Leetcode 1203: Sort Items by Groups Respecting Dependencies
107. Leetcode 1210: Minimum Moves to Reach Target with Rotations
108. Leetcode 1216: Valid Palindrome III
109. Leetcode 1224: Maximum Equal Frequency
110. Leetcode 1230: Toss Strange Coins
111. Leetcode 1234: Replace the Substring for Balanced String
112. Leetcode 1235: Maximum Profit in Job Scheduling
113. Leetcode 1245: Tree Diameter
114. Leetcode 1246: Palindrome Removal
115. Leetcode 1254: Number of Closed Islands
116. Leetcode 1255: Maximum Score Word Formed by Letters
117. Leetcode 1256: Encode Number
118. Leetcode 1257: Smallest Common Region
119. Leetcode 1258: Synonymous Sentences
120. Leetcode 1259: Handshakes That Don't Cross
121. Leetcode 1268: Search Suggestions System
122. Leetcode 1269: Number of Ways to Stay in the Same Place After Some Steps
123. Leetcode 1273: Delete Tree Nodes
124. Leetcode 1277: Count Square Submatrices with All Ones
125. Leetcode 1278: Palindrome Partitioning III
126. Leetcode 1282: Group the People Given the Group Size They Belong To 
127. Leetcode 1283: Find the Smallest Divisor Given a Threshold
128. Leetcode 1284: Minimum Number of Flips to Convert Binary Matrix to Zero Matrix
129. Leetcode 1300: Sum of Mutated Array Closest to Target
130. Leetcode 1301: Number of Paths with Max Score
131. Leetcode 1339: Maximum Product of Splitted Binary Tree
132. Leetcode 1371: Find the Longest Substring Containing Vowels in Even Counts 
133. Leetcode 1400: Construct K Palindrome Strings
134. Leetcode 1419: Minimum Number of Frogs Croaking
135. Leetcode 1448: Count Good Nodes in Binary Tree
136. Leetcode 1449: Form the Largest Integer with Digits that Add up to Target
137. Leetcode 1531: String Compression II
138. Leetcode 1542: Find Longest Awesome Substring
139. Leetcode 1547: Minimum Cost to Cut a Stick
140. Leetcode 1558: Minimum Numbers of Function Calls to Make Target Array 
141. Leetcode 1559: Detect Cycles in 2D Grid 
142. Leetcode 1562: Find the Latest Group with Size of M
143. Leetcode 1567: Maximum Length of Subarray With Positive Product
144. Leetcode 1569: Number of Ways to Reorder Array to Get Same BST
145. Leetcode 1579: Remove Max Number of Edges to Keep Graph fully Traversable
146. Leetcode 1584: Minimum Cost to Connect All Points
147. Leetcode 1585: Check If String Is Transformable With Substring Sorting Operations
148. Leetcode 1980: Find Unique Binary String
149. Leetcode 1981: Minimize the Difference Between Target and Chosen Elements
150. Leetcode 2104: Sum of Subarray Ranges