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Patterns for Coding Questions
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Introduction
Who should take this course?
Course Overview
Pattern: Sliding Window
Introduction
Maximum Sum Subarray of Size K (easy)
Smallest Subarray with a given sum (easy)
Longest Substring with K Distinct Characters (medium)
Fruits into Baskets (medium)
No-repeat Substring (hard)
Longest Substring with Same Letters after Replacement (hard)
Longest Subarray with Ones after Replacement (hard)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Problem Challenge 3
Solution Review: Problem Challenge 3
Problem Challenge 4
Solution Review: Problem Challenge 4
Pattern: Two Pointers
Introduction
Pair with Target Sum (easy)
Remove Duplicates (easy)
Squaring a Sorted Array (easy)
Triplet Sum to Zero (medium)
Triplet Sum Close to Target (medium)
Triplets with Smaller Sum (medium)
Subarrays with Product Less than a Target (medium)
Dutch National Flag Problem (medium)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Problem Challenge 3
Solution Review: Problem Challenge 3
Pattern: Fast and Slow Patterns
Introduction
LinkedList Cycle (easy)
Start of LinkedList Cycle (medium)
Happy Number (medium)
Middle of the LinkedList (easy)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Problem Challenge 3
Solution Review: Problem Challenge 3
Pattern: Merge Intervals
Introduction
Merge Intervals (medium)
Insert Interval (medium)
Intervals Intersection (medium)
Conflicting Appointments (medium)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Problem Challenge 3
Solution Review: Problem Challenge 3
Pattern: Cyclic Sort
Introduction
Cyclic Sort (easy)
Find the Missing Number (easy)
Find all Missing Numbers (easy)
Find the Duplicate Number (easy)
Find all Duplicate Numbers (easy)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Problem Challenge 3
Solution Review: Problem Challenge 3
Pattern: In-place Reversal of a LinkedList
Introduction
Reverse a LinkedList (easy)
Reverse a Sub-list (medium)
Reverse every K-element Sub-list (medium)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Pattern: Tree Breadth First Search
Introduction
Binary Tree Level Order Traversal (easy)
Reverse Level Order Traversal (easy)
Zigzag Traversal (medium)
Level Averages in a Binary Tree (easy)
Minimum Depth of a Binary Tree (easy)
Level Order Successor (easy)
Connect Level Order Siblings (medium)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Pattern: Tree Depth First Search
Introduction
Binary Tree Path Sum (easy)
All Paths for a Sum (medium)
Sum of Path Numbers (medium)
Path With Given Sequence (medium)
Count Paths for a Sum (medium)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Pattern: Two Heaps
Introduction
Find the Median of a Number Stream (medium)
Sliding Window Median (hard)
Maximize Capital (hard)
Problem Challenge 1
Solution Review: Problem Challenge 1
Pattern: Subsets
Introduction
Subsets (easy)
Subsets With Duplicates (easy)
Permutations (medium)
String Permutations by changing case (medium)
Balanced Parentheses (hard)
Unique Generalized Abbreviations (hard)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Problem Challenge 3
Solution Review: Problem Challenge 3
Pattern: Modified Binary Search
Introduction
Order-agnostic Binary Search (easy)
Ceiling of a Number (medium)
Next Letter (medium)
Number Range (medium)
Search in a Sorted Infinite Array (medium)
Minimum Difference Element (medium)
Bitonic Array Maximum (easy)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Problem Challenge 3
Solution Review: Problem Challenge 3
Pattern: Bitwise XOR
Introduction
Single Number (easy)
Two Single Numbers (medium)
Complement of Base 10 Number (medium)
Problem Challenge 1
Solution Review: Problem Challenge 1
Pattern: Top 'K' Elements
Introduction
Top 'K' Numbers (easy)
Kth Smallest Number (easy)
'K' Closest Points to the Origin (easy)
Connect Ropes (easy)
Top 'K' Frequent Numbers (medium)
Frequency Sort (medium)
Kth Largest Number in a Stream (medium)
'K' Closest Numbers (medium)
Maximum Distinct Elements (medium)
Sum of Elements (medium)
Rearrange String (hard)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Problem Challenge 3
Solution Review: Problem Challenge 3
Pattern: K-way merge
Introduction
Merge K Sorted Lists (medium)
Kth Smallest Number in M Sorted Lists (Medium)
Kth Smallest Number in a Sorted Matrix (Hard)
Smallest Number Range (Hard)
Problem Challenge 1
Solution Review: Problem Challenge 1
Pattern : 0/1 Knapsack (Dynamic Programming)
Introduction
0/1 Knapsack (medium)
Equal Subset Sum Partition (medium)
Subset Sum (medium)
Minimum Subset Sum Difference (hard)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Pattern: Topological Sort (Graph)
Introduction
Topological Sort (medium)
Tasks Scheduling (medium)
Tasks Scheduling Order (medium)
All Tasks Scheduling Orders (hard)
Alien Dictionary (hard)
Problem Challenge 1
Solution Review: Problem Challenge 1
Problem Challenge 2
Solution Review: Problem Challenge 2
Miscellaneous
Kth Smallest Number (hard)
Conclusions
Where to Go from Here
Home
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Problem Challenge 1
Problem Challenge 1
Quadruple Sum to Target (medium)
Given an array of unsorted numbers and a target number, find
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