Blind 75 LeetCode Study Plan

Blind 75 is the classic 75-problem list that covers the core patterns asked in software engineering interviews: arrays and hashing, two pointers, sliding windows, binary search, trees, tries, backtracking, graphs, dynamic programming, intervals, greedy, and bit manipulation.

In Dokicode, the 75 problems are grouped into 18 topic chapters. Any problem you have already solved on the 12-plan learning route or another interview list is automatically marked done, and LeetCode Premium problems are flagged as optional so they never block your progress.

75 problemsRating 1161–215918 Topics

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Arrays and Hashing

Problem	Difficulty / Rating
217. Contains Duplicate	Easy
242. Valid Anagram	Easy
1. Two Sum	1161
49. Group Anagrams	Medium
347. Top K Frequent Elements	Medium
238. Product of Array Except Self	Medium
271. Encode and Decode Strings Premium (Optional)	Medium
128. Longest Consecutive Sequence	Medium

Two Pointers

Problem	Difficulty / Rating
125. Valid Palindrome	1263
15. 3sum	1263
11. Container with Most Water	1263

Sliding Window

Problem	Difficulty / Rating
121. Best Time to Buy AND Sell Stock	Easy
3. Longest Substring Without Repeating Characters	1263
424. Longest Repeating Character Replacement	1787
76. Minimum Window Substring	1592

Stack

Problem	Difficulty / Rating
20. Valid Parentheses	1242

Binary Search

Problem	Difficulty / Rating
153. Find Minimum in Rotated Sorted Array	Medium
33. Search in Rotated Sorted Array	Medium

Linked Lists

Problem	Difficulty / Rating
206. Reverse Linked List	Easy
21. Merge Two Sorted Lists	Easy
143. Reorder List	Medium
19. Remove Nth Node From End of List	Medium
141. Linked List Cycle	Easy
23. Merge K Sorted Lists	1818

Trees

Problem	Difficulty / Rating
226. Invert Binary Tree	Easy
104. Maximum Depth of Binary Tree	Easy
100. Same Tree	Easy
572. Subtree of Another Tree	Easy
235. Lowest Common Ancestor of a Binary Search Tree	Medium
102. Binary Tree Level Order Traversal	Medium
98. Validate Binary Search Tree	Medium
230. Kth Smallest Element in a Bst	Medium
105. Construct Binary Tree From Preorder AND Inorder Traversal	Medium
124. Binary Tree Maximum Path Sum	Hard
297. Serialize AND Deserialize Binary Tree	Hard

Tries

Problem	Difficulty / Rating
208. Implement Trie Prefix Tree	1180
211. Design Add AND Search Words Data Structure	1725
212. Word Search II	1725

Heaps

Problem	Difficulty / Rating
295. Find Median From Data Stream	2159

Backtracking

Problem	Difficulty / Rating
39. Combination Sum	Medium
79. Word Search	Medium

Graphs

Problem	Difficulty / Rating
200. Number of Islands	Medium
133. Clone Graph	Medium
417. Pacific Atlantic Water Flow	1900
207. Course Schedule	Medium
323. Number of Connected Components in an Undirected Graph Premium (Optional)	Medium
261. Graph Valid Tree Premium (Optional)	Medium

Advanced Graphs

Problem	Difficulty / Rating
269. Alien Dictionary Premium (Optional)	Hard

1-D DP

Problem	Difficulty / Rating
70. Climbing Stairs	Easy
198. House Robber	Medium
213. House Robber II	Medium
5. Longest Palindromic Substring	Medium
647. Palindromic Substrings	Medium
91. Decode Ways	Medium
322. Coin Change	Medium
152. Maximum Product Subarray	Medium
139. Word Break	Medium
300. Longest Increasing Subsequence	Medium

2-D DP

Problem	Difficulty / Rating
62. Unique Paths	Medium
1143. Longest Common Subsequence	Medium

Greedy

Problem	Difficulty / Rating
53. Maximum Subarray	Medium
55. Jump Game	Medium

Intervals

Problem	Difficulty / Rating
57. Insert Interval	Medium
56. Merge Intervals	Medium
435. Non Overlapping Intervals	1700
252. Meeting Rooms Premium (Optional)	Easy
253. Meeting Rooms II Premium (Optional)	Medium

Math and Geometry

Problem	Difficulty / Rating
48. Rotate Image	Medium
54. Spiral Matrix	Medium
73. Set Matrix Zeroes	Medium

Bit Manipulation

Problem	Difficulty / Rating
191. Number of 1 Bits	Easy
338. Counting Bits	Easy
190. Reverse Bits	Easy
268. Missing Number	Easy
371. Sum of Two Integers	Medium

Select Blind 75 when signing your study contract (or switch to it anytime in the Study Plan drawer) and your heroine will bring you the next unsolved problem topic by topic.

Ratings come from zerotrac's LeetCode contest ratings. Classic pre-contest problems show their LeetCode difficulty level instead.

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