Blind 75

A curated list of 75 essential coding problems for technical interviews.

Total: 75 problems across 10 categories

array(10)

#	Problem	Difficulty	Video
1	Two Sum	easy
121	Best Time To Buy And Sell Stock 1 - only one transaction	easy
217	Contains Duplicate 1 - Check if array has duplicates	easy
11	Container With Most Water	medium
15	3Sum0 - Find three elements in an array that sum to a zero	medium
33	Search in Rotated Sorted Array	medium
53	Maximum Subarray Sum	medium
152	Maximum Product Subarray	medium
153	Find Minimum in Rotated Sorted Array	medium
238	Product of Array Except Self	medium

string(10)

#	Problem	Difficulty	Video
20	Valid Parentheses	easy
125	Valid Palindrome	easy
242	Valid Anagram	easy
3	Longest Substring Without Repeating Characters	medium
5	Longest Palindromic Substring	medium
49	Group Anagrams	medium
271	Encode and Decode Strings	medium
424	Longest Substring with Same Letters after Replacement	medium
647	Palindromic Substrings	medium
76	Minimum Window Substring	hard

bit manipulation(5)

#	Problem	Difficulty	Video
190	Reverse Bits	easy
191	Number of 1 Bits	easy
268	Missing Number	easy
338	Counting Bits	easy
371	Sum of Two Integers	medium

linked list(6)

#	Problem	Difficulty	Video
21	Merge Two Sorted Linked Lists	easy
141	Linked List Cycle 1 - Detect Cycle	easy
206	Reverse Linked List	easy
19	Remove Nth Node From End of List	medium
143	Reorder List such that i-th element points to n-i-th element	medium
23	Merge K Sorted Lists	hard

tree(14)

#	Problem	Difficulty	Video
100	Same Tree	easy
104	Maximum Depth of Binary Tree	easy
226	Invert Binary Tree	easy
572	Subtree of Another Tree	easy
98	Validate Binary Search Tree	medium
102	Binary Tree Level Order Traversal - Level by Level	medium
105	Construct Binary Tree from Inorder and Preorder Traversal	medium
208	Implement Trie	medium
211	Design Add and Search Words Data Structure	medium
230	Kth Smallest Element in a BST	medium
235	Lowest Common Ancestor of a Binary Search Tree	medium
124	Binary Tree Path Sum - Maximum between any two nodes	hard
212	Word Search 2 - Return All Words	hard
297	Serialize and Deserialize Binary Tree	hard

graph(8)

#	Problem	Difficulty	Video
128	Longest Consecutive Sequence	medium	-
133	Clone Undirected Graph	medium	-
200	Number of Islands	medium
207	Course Schedule 1 - Is it Possible	medium	-
261	Graph Valid Tree	medium	-
323	Number of Connected Components in an Undirected Graph	medium	-
417	Pacific Atlantic Water Flow	medium	-
269	Alien Dictionary	hard	-

interval(5)

#	Problem	Difficulty	Video
252	Meeting Rooms 1 - Can person attend all meetings	easy	-
56	Merge Overlapping Intervals	medium	-
57	Insert Interval	medium	-
253	Maximum Intervals Overlap Count	medium	-
435	Non-overlapping Intervals	medium	-

dynamic programming(11)

#	Problem	Difficulty	Video
70	Climbing Stairs - Take atmost 2 Steps	easy
39	Combination Sum 1	medium
55	Jump Game 1 - Check if it reaches last index	medium
62	Unique Paths in Grid 1 - Count all paths moving right or down	medium
91	Decode Ways	medium
139	Word Break 1 - Check if word is breakable	medium
198	House Robber	medium
213	House Robber 2 - Houses in circle	medium
300	Longest Increasing Subsequence	medium
322	Coin Change with Fewest Number of Coins Given Infinite Supply	medium
1143	Longest Common Subsequence LCS 1 - Get Length	medium

heap priority queue(2)

#	Problem	Difficulty	Video
347	Top K Frequent Elements	medium
295	Find Median from Data Stream	hard	-

matrix(4)

#	Problem	Difficulty	Video
44	Rotate n x n matrix by 90 degrees	medium
54	Spiral Matrix 1 - Return	medium
73	Set Matrix Zeros	medium
79	Word Search 1 - Find if word exists	medium