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SDE 250

Adds the classics that Indian product-company interviews lean on, plus implementation-heavy staples.

117h of work left3 per day to finish in 14 weeks250 problems
Easy
0
of 49
Medium
0
of 169
Hard
0
of 32
By topic
Arrays0/14
Strings0/14
Hashing0/3
Sorting0/3
Binary Search0/11
Two Pointers0/10
Sliding Window0/8
Prefix Sum0/3
Matrix0/6
Intervals0/6
Linked List0/14
Stacks & Queues0/13
Trees0/23
Binary Search Tree0/8
Heap / Priority Queue0/8
Graphs0/26
Greedy0/10
Dynamic Programming0/28
Recursion & Backtracking0/14
Tries0/5
Bit Manipulation0/7
Math & Number Theory0/5
Design (LLD)0/8
Advanced0/3
Next phase: DSA 450

Adds 200 problems on top of this one.

The sheet

Click the circle on any row to cycle status: unsolved, solved, attempted, revisit.

0 / 250 solved
Arrays0 / 14
1
Best Time to Buy and Sell Stock
EArrays
2
Longest Consecutive Sequence
MArrays
3
Maximum Subarray
MArrays
4
Product of Array Except Self
MArrays
5
Contains Duplicate
EArrays
6
Maximum Product Subarray
MArrays
7
Find the Duplicate Number
MArrays
8
Majority Element
EArrays
9
Next Permutation
MArrays
10
Rotate Array
MArrays
11
Best Time to Buy and Sell Stock II
MArrays
12
First Missing Positive
HArrays
13
Find All Duplicates in an Array
MArrays
14
Find All Numbers Disappeared in an Array
EArrays
Strings0 / 14
1
Group Anagrams
MStrings
2
Longest Palindromic Substring
MStrings
3
Palindromic Substrings
MStrings
4
Valid Anagram
EStrings
5
Valid Palindrome
EStrings
6
Find All Anagrams in a String
MStrings
7
Reverse Words in a String
MStrings
8
Roman to Integer
EStrings
9
String to Integer (atoi)
MStrings
10
Valid Palindrome II
EStrings
11
Find the Index of the First Occurrence in a String
EStrings
12
First Unique Character in a String
EStrings
13
Isomorphic Strings
EStrings
14
Longest Common Prefix
EStrings
Hashing0 / 3
1
Two Sum
EHashing
2
Subarray Sum Equals K
MHashing
3
Happy Number
EHashing
Sorting0 / 3
1
Implement Merge Sort
MSorting
2
Implement Quick Sort
MSorting
3
Largest Number
MSorting
Binary Search0 / 11
1
Search in Rotated Sorted Array
MBinary Search
2
Find Minimum in Rotated Sorted Array
MBinary Search
3
Binary Search
EBinary Search
4
Find First and Last Position of Element in Sorted Array
MBinary Search
5
Find Peak Element
MBinary Search
6
Koko Eating Bananas
MBinary Search
7
Median of Two Sorted Arrays
HBinary Search
8
Allocate Minimum Number of Pages
HBinary Search
9
Capacity To Ship Packages Within D Days
MBinary Search
10
Aggressive Cows
HBinary Search
11
Kth Smallest Element in a Sorted Matrix
MBinary Search
Two Pointers0 / 10
1
3Sum
MTwo Pointers
2
Container With Most Water
MTwo Pointers
3
Trapping Rain Water
HTwo Pointers
4
Merge Sorted Array
ETwo Pointers
5
Move Zeroes
ETwo Pointers
6
Sort Colors
MTwo Pointers
7
Two Sum II - Input Array Is Sorted
MTwo Pointers
8
Remove Duplicates from Sorted Array
ETwo Pointers
9
3Sum Closest
MTwo Pointers
10
4Sum
MTwo Pointers
Sliding Window0 / 8
1
Longest Substring Without Repeating Characters
MSliding Window
2
Minimum Window Substring
HSliding Window
3
Longest Repeating Character Replacement
MSliding Window
4
Sliding Window Maximum
HSliding Window
5
Longest Substring with At Most K Distinct Characterspremium
MSliding Window
6
Max Consecutive Ones III
MSliding Window
7
Minimum Size Subarray Sum
MSliding Window
8
Permutation in String
MSliding Window
Prefix Sum0 / 3
1
Contiguous Array
MPrefix Sum
2
Longest Subarray with Sum K
MPrefix Sum
3
Find Pivot Index
EPrefix Sum
Matrix0 / 6
1
Rotate Image
MMatrix
2
Spiral Matrix
MMatrix
3
Word Search
MMatrix
4
Set Matrix Zeroes
MMatrix
5
Search a 2D Matrix
MMatrix
6
Game of Life
MMatrix
Intervals0 / 6
1
Meeting Rooms IIpremium
MIntervals
2
Merge Intervals
MIntervals
3
Insert Interval
MIntervals
4
Meeting Roomspremium
EIntervals
5
Non-overlapping Intervals
MIntervals
6
Interval List Intersections
MIntervals
Linked List0 / 14
1
Linked List Cycle
ELinked List
2
Merge k Sorted Lists
HLinked List
3
Merge Two Sorted Lists
ELinked List
4
Remove Nth Node From End of List
MLinked List
5
Reverse Linked List
ELinked List
6
Reorder List
MLinked List
7
Add Two Numbers
MLinked List
8
Copy List with Random Pointer
MLinked List
9
Intersection of Two Linked Lists
ELinked List
10
Linked List Cycle II
MLinked List
11
Palindrome Linked List
ELinked List
12
Reverse Nodes in k-Group
HLinked List
13
Reverse Linked List II
MLinked List
14
Sort List
MLinked List
Stacks & Queues0 / 13
1
Valid Parentheses
EStacks & Queues
2
Largest Rectangle in Histogram
HStacks & Queues
3
Min Stack
MStacks & Queues
4
Daily Temperatures
MStacks & Queues
5
Evaluate Reverse Polish Notation
MStacks & Queues
6
Car Fleet
MStacks & Queues
7
Asteroid Collision
MStacks & Queues
8
Basic Calculator II
MStacks & Queues
9
Decode String
MStacks & Queues
10
Longest Valid Parentheses
HStacks & Queues
11
Simplify Path
MStacks & Queues
12
Maximal Rectangle
HStacks & Queues
13
The Celebrity Problem
MStacks & Queues
Trees0 / 23
1
Binary Tree Level Order Traversal
MTrees
2
Binary Tree Maximum Path Sum
HTrees
3
Invert Binary Tree
ETrees
4
Maximum Depth of Binary Tree
ETrees
5
Serialize and Deserialize Binary Tree
HTrees
6
Construct Binary Tree from Preorder and Inorder Traversal
MTrees
7
Same Tree
ETrees
8
Subtree of Another Tree
ETrees
9
Binary Tree Right Side View
MTrees
10
Diameter of Binary Tree
ETrees
11
Lowest Common Ancestor of a Binary Tree
MTrees
12
Balanced Binary Tree
ETrees
13
Binary Tree Inorder Traversal
ETrees
14
Count Good Nodes in Binary Tree
MTrees
15
All Nodes Distance K in Binary Tree
MTrees
16
Binary Tree Zigzag Level Order Traversal
MTrees
17
Flatten Binary Tree to Linked List
MTrees
18
Path Sum III
MTrees
19
Symmetric Tree
ETrees
20
Vertical Order Traversal of a Binary Tree
HTrees
21
Binary Tree Postorder Traversal
ETrees
22
Binary Tree Preorder Traversal
ETrees
23
Boundary Traversal of Binary Tree
MTrees
Binary Search Tree0 / 8
1
Kth Smallest Element in a BST
MBinary Search Tree
2
Validate Binary Search Tree
MBinary Search Tree
3
Lowest Common Ancestor of a Binary Search Tree
MBinary Search Tree
4
Binary Search Tree Iterator
MBinary Search Tree
5
Delete Node in a BST
MBinary Search Tree
6
Inorder Successor in BSTpremium
MBinary Search Tree
7
Convert Sorted Array to Binary Search Tree
EBinary Search Tree
8
Insert into a Binary Search Tree
MBinary Search Tree
Heap / Priority Queue0 / 8
1
Find Median from Data Stream
HHeap / Priority Queue
2
Top K Frequent Elements
MHeap / Priority Queue
3
K Closest Points to Origin
MHeap / Priority Queue
4
Kth Largest Element in an Array
MHeap / Priority Queue
5
Task Scheduler
MHeap / Priority Queue
6
Reorganize String
MHeap / Priority Queue
7
Implement a Binary Heap
MHeap / Priority Queue
8
Kth Largest Element in a Stream
EHeap / Priority Queue
Graphs0 / 26
1
Clone Graph
MGraphs
2
Course Schedule
MGraphs
3
Number of Islands
MGraphs
4
Alien Dictionarypremium
HGraphs
5
Graph Valid Treepremium
MGraphs
6
Number of Connected Components in an Undirected Graphpremium
MGraphs
7
Pacific Atlantic Water Flow
MGraphs
8
Course Schedule II
MGraphs
9
Rotting Oranges
MGraphs
10
Cheapest Flights Within K Stops
MGraphs
11
Longest Increasing Path in a Matrix
HGraphs
12
Min Cost to Connect All Points
MGraphs
13
Network Delay Time
MGraphs
14
Redundant Connection
MGraphs
15
Word Ladder
HGraphs
16
Reconstruct Itinerary
HGraphs
17
Swim in Rising Water
HGraphs
18
Walls and Gatespremium
MGraphs
19
01 Matrix
MGraphs
20
Accounts Merge
MGraphs
21
Detect Cycle in a Directed Graph
MGraphs
22
Detect Cycle in an Undirected Graph
MGraphs
23
Evaluate Division
MGraphs
24
Is Graph Bipartite
MGraphs
25
Number of Provinces
MGraphs
26
Surrounded Regions
MGraphs
Greedy0 / 10
1
Jump Game
MGreedy
2
Gas Station
MGreedy
3
Jump Game II
MGreedy
4
Partition Labels
MGreedy
5
Hand of Straights
MGreedy
6
Job Sequencing Problem
MGreedy
7
Minimum Platforms
MGreedy
8
N Meetings in One Room
EGreedy
9
Candy
HGreedy
10
Fractional Knapsack
MGreedy
Dynamic Programming0 / 28
1
Climbing Stairs
EDynamic Programming
2
Coin Change
MDynamic Programming
3
Decode Ways
MDynamic Programming
4
House Robber
MDynamic Programming
5
Longest Common Subsequence
MDynamic Programming
6
Longest Increasing Subsequence
MDynamic Programming
7
Unique Paths
MDynamic Programming
8
Word Break
MDynamic Programming
9
House Robber II
MDynamic Programming
10
Combination Sum IV
MDynamic Programming
11
0/1 Knapsack
MDynamic Programming
12
Edit Distance
MDynamic Programming
13
Partition Equal Subset Sum
MDynamic Programming
14
Best Time to Buy and Sell Stock with Cooldown
MDynamic Programming
15
Coin Change II
MDynamic Programming
16
Minimum Path Sum
MDynamic Programming
17
Target Sum
MDynamic Programming
18
Min Cost Climbing Stairs
EDynamic Programming
19
Maximal Square
MDynamic Programming
20
Regular Expression Matching
HDynamic Programming
21
Wildcard Matching
HDynamic Programming
22
Best Time to Buy and Sell Stock IV
HDynamic Programming
23
Burst Balloons
HDynamic Programming
24
Distinct Subsequences
HDynamic Programming
25
Interleaving String
MDynamic Programming
26
Longest Palindromic Subsequence
MDynamic Programming
27
Matrix Chain Multiplication
HDynamic Programming
28
Perfect Sum Problem
MDynamic Programming
Recursion & Backtracking0 / 14
1
Combination Sum
MRecursion & Backtracking
2
Generate Parentheses
MRecursion & Backtracking
3
Letter Combinations of a Phone Number
MRecursion & Backtracking
4
Permutations
MRecursion & Backtracking
5
Subsets
MRecursion & Backtracking
6
Combination Sum II
MRecursion & Backtracking
7
N-Queens
HRecursion & Backtracking
8
Palindrome Partitioning
MRecursion & Backtracking
9
Subsets II
MRecursion & Backtracking
10
Sudoku Solver
HRecursion & Backtracking
11
Combinations
MRecursion & Backtracking
12
M-Coloring Problem
MRecursion & Backtracking
13
Permutation Sequence
HRecursion & Backtracking
14
Rat in a Maze Problem
MRecursion & Backtracking
Tries0 / 5
1
Implement Trie (Prefix Tree)
MTries
2
Design Add and Search Words Data Structure
MTries
3
Word Search II
HTries
4
Search Suggestions System
MTries
5
Maximum XOR of Two Numbers in an Array
MTries
Bit Manipulation0 / 7
1
Counting Bits
EBit Manipulation
2
Missing Number
EBit Manipulation
3
Number of 1 Bits
EBit Manipulation
4
Reverse Bits
EBit Manipulation
5
Single Number
EBit Manipulation
6
Sum of Two Integers
MBit Manipulation
7
Divide Two Integers
MBit Manipulation
Math & Number Theory0 / 5
1
Pow(x, n)
MMath & Number Theory
2
Reverse Integer
MMath & Number Theory
3
Count Primes
MMath & Number Theory
4
GCD of Two Numbers
EMath & Number Theory
5
Sieve of Eratosthenes
MMath & Number Theory
Design (LLD)0 / 8
1
Encode and Decode Stringspremium
MDesign (LLD)
2
LRU Cache
MDesign (LLD)
3
Time Based Key-Value Store
MDesign (LLD)
4
Design Twitter
MDesign (LLD)
5
Implement Queue using Stacks
EDesign (LLD)
6
Insert Delete GetRandom O(1)
MDesign (LLD)
7
Random Pick with Weight
MDesign (LLD)
8
Design HashMap
EDesign (LLD)
Advanced0 / 3
1
Minimum Spanning Tree (Kruskal)
MAdvanced
2
Union-Find with Rank and Path Compression
MAdvanced
3
Range Sum Query - Mutable
MAdvanced