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
#easy
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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
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
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