LeetCode Interval Problems: Merge, Insert, and Schedule
Master interval problems on LeetCode: sorting, merging, inserting, and scheduling with templates, visual walkthroughs, and complexity analysis.
·6 min read · #leetcode#intervals#algorithms
#leetcode
84 posts · page 1 of 2
LeetCode Two Pointer Patterns: The Complete Guide
Master every two pointer pattern for LeetCode: opposite-end, same-direction, and fast/slow pointers with templates, complexity analysis, and 15+ mapped problems.
·7 min read · #leetcode#two-pointers#algorithms
Backtracking Patterns: Permutations, Combinations, Subsets, and Constraints
Master backtracking with reusable templates for permutations, combinations, subsets, and constraint satisfaction problems on LeetCode.
·7 min read · #leetcode#backtracking#recursion
Binary Search Patterns: Search Space, Boundaries, and Rotated Arrays
Master binary search patterns for LeetCode including search space reduction, boundary finding, rotated array search, and practical templates.
·8 min read · #leetcode#binary-search#algorithms
Dynamic Programming Patterns: 1D, 2D, Memoization, and Tabulation
Master dynamic programming with 1D and 2D patterns, memoization vs tabulation approaches, and solutions to classic LeetCode DP problems.
·9 min read · #leetcode#dynamic-programming#algorithms
Graph Traversal Patterns: BFS, DFS, Topological Sort, and Shortest Path
Master graph traversal patterns for LeetCode including BFS, DFS, topological sort, Dijkstra, and practical templates with solutions.
·7 min read · #leetcode#graphs#bfs
Greedy Algorithm Patterns: Interval Scheduling, Activity Selection, and More
Master greedy algorithm patterns for LeetCode including interval scheduling, activity selection, jump games, and proving greedy correctness.
·7 min read · #leetcode#greedy#intervals
Sliding Window Patterns: Fixed, Variable, and Two Pointer Variants
Master the sliding window technique with fixed and variable window patterns, two pointer variants, and reusable templates for solving LeetCode problems.
·8 min read · #leetcode#sliding-window#two-pointers
Tree Traversal Patterns: Inorder, Preorder, Postorder, Level-Order, and Morris
Master every tree traversal method with recursive, iterative, and Morris traversal implementations, plus classic LeetCode tree problems.
·7 min read · #leetcode#trees#traversal
Stack and Queue Patterns: Monotonic Stack, Min Stack, and Queue Tricks
Master stack and queue patterns for LeetCode including monotonic stacks, min stacks, queue implementations, and practical templates.
·8 min read · #leetcode#stack#queue
Best Time to Buy and Sell Stock II — Greedy Sum of Positive Deltas
Solve the multi-transaction stock problem with the greedy peak-valley insight: sum every positive daily delta. Includes complexity analysis and DP alternative.
·4 min read · #leetcode#arrays#greedy
Capacity to Ship Packages Within D Days — Binary Search
Solve Capacity to Ship Packages Within D Days by binary searching the ship capacity. Includes feasibility check, tight bounds, and a worked example.
·5 min read · #leetcode#binary-search#arrays
Contains Duplicate — The Hash Set Solution
A clear walkthrough of the Contains Duplicate problem, covering brute force, sorting, and the optimal hash set approach with complexity analysis.
·4 min read · #leetcode#arrays#hash-set
Find Peak Element — Binary Search on Slope
Solve Find Peak Element in O(log n) by binary searching on the slope direction. Includes diagram and edge cases.
·5 min read · #leetcode#binary-search#arrays
First Bad Version — Classic Binary Search
Solve First Bad Version with binary search and overflow-safe midpoint calculation. Includes API constraints and complexity.
·4 min read · #leetcode#binary-search#easy
Koko Eating Bananas — Binary Search on Answer
Solve Koko Eating Bananas by binary searching the eating speed. Includes the monotonic predicate, ceiling division, and complexity.
·5 min read · #leetcode#binary-search#arrays
Majority Element — Boyer-Moore Voting
Solve Majority Element in O(n) time and O(1) space using Boyer-Moore majority vote. Includes intuition, walkthrough, and edge cases.
·4 min read · #leetcode#arrays#boyer-moore
Missing Number — Sum and XOR Tricks
Solve the Missing Number problem with three approaches: hashing, Gauss sum formula, and XOR. Includes complexity analysis and interview tips.
·5 min read · #leetcode#arrays#math
Move Zeroes — Two-Pointer In-Place Solution
Solve Move Zeroes in O(n) time and O(1) space using a write pointer. Includes walkthrough, edge cases, and interview tips.
·4 min read · #leetcode#arrays#two-pointers
Pascal's Triangle — Row-by-Row Construction
Build Pascal's Triangle in O(n^2) time using simple row-by-row addition. Includes a clear diagram, edge cases, and complexity analysis.
·5 min read · #leetcode#arrays#math
Plus One — Carry Propagation Done Right
Add one to a big integer stored as a digit array by walking from the back. Includes carry handling, the all-nines edge case, and complexity analysis.
·4 min read · #leetcode#arrays#math
Remove Duplicates from Sorted Array — Write-Pointer Pattern
Solve Remove Duplicates from Sorted Array in O(n) time and O(1) space with the two-pointer write-pointer pattern. Includes walkthrough, edge cases, and complexity.
·4 min read · #leetcode#arrays#two-pointers
Search a 2D Matrix — Binary Search in One Pass
Solve Search a 2D Matrix by treating the sorted matrix as a flat sorted array and binary searching. Includes index arithmetic and complexity.
·5 min read · #leetcode#matrix#binary-search
Set Matrix Zeroes — O(1) Space In-Place Trick
Solve Set Matrix Zeroes in place using the first row and column as markers. Includes a step-by-step walkthrough and edge cases.
·6 min read · #leetcode#matrix#arrays
Single Number — The XOR Trick Explained
Solve the Single Number problem in O(n) time and O(1) space using XOR. Includes a walkthrough, edge cases, and follow-up variants.
·4 min read · #leetcode#arrays#bit-manipulation
How to Grind LeetCode Effectively: Patterns Over Volume
Stop doing 500 random problems. Use spaced repetition, study patterns instead of volume, and run weekly mock interviews to make every LeetCode hour count.
·5 min read · #career#leetcode#interview-prep
Find Minimum in Rotated Sorted Array — Binary Search
Solve Find Minimum in Rotated Sorted Array in logarithmic time with a modified binary search. Learn the pivot-finding invariant, edge cases, and how to extend the pattern to related problems.
·5 min read · #dsa#leetcode#binary-search
Fizz Buzz — A Clean, Extensible Solution
Solve Fizz Buzz with clean code and explore the string-concatenation pattern that avoids nested if-else. Python, Java, C++, and complexity analysis included.
·5 min read · #dsa#leetcode#beginners
Find Median from Data Stream — Two-Heaps Pattern
Solve Find Median from Data Stream with two heaps. Learn the balance invariant, why it gives O(log n) inserts and O(1) median, and the common pitfalls.
·5 min read · #dsa#leetcode#heap
Jump Game — Greedy Max-Reach Beats DP
Solve Jump Game with a single-pass greedy max-reach approach. Compare it against the dynamic programming solution and learn when greedy is provably optimal.
·4 min read · #dsa#leetcode#greedy
Maximum Product Subarray — Tracking Min and Max
Solve Maximum Product Subarray in linear time by tracking running min and max. Learn why negative numbers flip the role of min and max and see clean code.
·5 min read · #dsa#leetcode#dynamic-programming
Meeting Rooms II — Heap and Sweep Line
Solve Meeting Rooms II two ways: a min-heap of end times and a sweep-line over start and end events. Learn when each shines and how to pick in interviews.
·4 min read · #dsa#leetcode#heap
Merge Intervals — Sort and Sweep
Walk through Merge Intervals step by step. Brute force vs the optimal sort-and-sweep approach, edge cases, and clean code you can ship in an interview.
·5 min read · #dsa#leetcode#intervals
Palindrome Number — Without Converting to a String
Detect integer palindromes by reversing half the digits with integer math. Learn why string conversion is discouraged and how to handle negatives and trailing zeros.
·6 min read · #dsa#leetcode#math
Reverse String — Two-Pointer In-Place Solution
Solve the Reverse String problem in place using the two-pointer technique. Walkthrough, complexity analysis, edge cases, and clean Java, Python, and C++ implementations.
·4 min read · #dsa#leetcode#two-pointers
Rotate Array — The Triple-Reverse Trick
Rotate an array by k steps in O(1) extra space using the triple-reverse trick. Compare it with the extra-array approach and learn why this pattern keeps showing up.
·5 min read · #dsa#leetcode#arrays
3Sum — Sort and Two Pointers, Step by Step
A careful walkthrough of 3Sum using sort plus two pointers. We handle duplicate triplets cleanly and avoid the classic off-by-one traps.
·7 min read · #dsa#leetcode#two-pointers
Best Time to Buy and Sell Stock — One-Pass Min Tracker
Walk through Best Time to Buy and Sell Stock. We go from the quadratic brute force to a clean one-pass solution tracking the running minimum.
·5 min read · #dsa#leetcode#arrays
Binary Tree Level Order Traversal — Queue Size Snapshot
The queue-with-size BFS pattern, why DFS still works, and how this template extends to zigzag and right-side view.
·5 min read · #dsa#leetcode#trees
Climbing Stairs: Fibonacci in Disguise
Walk through Climbing Stairs from brute force recursion to bottom-up DP, with edge cases, complexity analysis, and an interview script.
·5 min read · #dsa#leetcode#dynamic-programming
Clone Graph — DFS With a Node-to-Copy Hash Map
Why a hash map from original to copy is the entire idea, plus the BFS variant for stack-limited environments.
·5 min read · #dsa#leetcode#graphs
Coin Change: Bottom-Up DP Explained
Walk through Coin Change with brute force recursion, memoization, and bottom-up DP. Includes complexity analysis and interview script.
·6 min read · #dsa#leetcode#dynamic-programming
Container With Most Water — Two-Pointer Walkthrough
Solve Container With Most Water with the two-pointer technique. We prove correctness and contrast it with the quadratic brute force.
·6 min read · #dsa#leetcode#two-pointers
Combination Sum: Backtracking With Reuse
Solve Combination Sum with a clean backtracking template. Pruning, duplicate avoidance, complexity discussion, and interview script.
·5 min read · #dsa#leetcode#backtracking
Course Schedule — Topological Sort With DFS
Detect cycles and produce a valid course order using DFS-based topological sort. Includes BFS Kahn alternative and interview script.
·6 min read · #dsa#leetcode#graphs
Edit Distance: 2D DP Step by Step
Edit Distance fully unpacked — the three-operation recurrence, the 2D table, and the rolling-array space optimization that makes interviewers nod.
·6 min read · #dsa#leetcode#dp
Daily Temperatures — Monotonic Stack Pattern
Solve Daily Temperatures with a monotonic decreasing stack of indices. Includes brute force comparison, walkthrough, complexity, and interview tips.
·6 min read · #dsa#leetcode#stack
Group Anagrams — Hash Map of Canonical Keys
Solve the Group Anagrams problem cleanly with a hash map keyed by sorted strings or character counts. Includes complexity analysis and interview talking points.
·6 min read · #dsa#leetcode#hashing