Array

Foundational array problems covering sliding window, prefix sums, two pointers, subarrays, rotations, and core interview patterns.

Filter by difficulty:
Design
•
Design an O(1) Data Structure for Insert, Delete & Random Medium
Solution
Moore’s Voting Algorithm
•
Majority Element (> n/2) Easy
Solution
•
Majority Element II (> n/3) Medium
Solution
Array Product
•
Product of Array Except Self Medium
Solution
•
Minimum Product Subset Medium
Solution
•
Maximum Product Subarray Medium
Solution
Binary Array
•
Max Consecutive Ones (flip at most K zeros) Medium
Solution
•
Max Consecutive Ones (flip one subarray of zeros) Medium
Solution not available
•
Largest subarray with equal continuous 0s and 1s Medium
Solution not available
•
Largest subarray with equal 0s and 1s Medium
Solution
House Robber
•
House Robber (Linear) Medium
Solution
•
House Robber II (Circular) Medium
Solution
•
House Robber III (Binary Tree) Medium
Solution
Numbers
•
Reorder array using index array Easy
Solution not available
•
Move negatives to start and positives to end Easy
Solution
•
Alternate negative and positive numbers Medium
Solution not available
•
First Missing Positive Hard
Solution
•
Smallest positive missing from subset sum Hard
Solution
•
Longest Consecutive Sequence Medium
Solution
Rotation
•
Rotate an Array Medium
Solution
•
Range Sum Query with Rotation Medium
Solution
•
Max Sum of a[i] × i using rotations Medium
Solution
Subarray
•
Kadane’s Algorithm Easy
Solution
•
Subarrays with Sum Divisible by K Medium
Solution
•
Subarray Sum Equals K Medium
Solution
•
Max Subarray Sum ≤ K Medium
Solution
•
Unique Elements Subarray with Maximum Sum Medium
Solution
•
Max Sum from Two Arrays Hard
Solution
•
Longest Subarray with Maximum AND Medium
Solution
•
Gas Station Tour Medium
Solution
Tuple Sum
•
Two Sum (Unsorted) Easy
Solution
•
Two Sum (Sorted) Easy
Solution
•
Two Sum (Stream) Easy
Solution
•
Two Sum (BST) Easy
Solution
•
Pair Sum Closest to X Medium
Solution
•
Pair Sum Divisible by K Medium
Solution
•
3 Sum Medium
Solution
•
3 Sum Closest Medium
Solution
•
4 Sum Medium
Solution
Two Numbers
•
Maximum Difference Between Two Numbers Easy
Solution
•
Minimum Difference Between Two Numbers Easy
Solution
•
Contains Duplicate II Medium
Solution
•
Contains Duplicate III Hard
Solution
Two Pointers
•
Trapping Rain Water Medium
Solution
•
Maximum Fruits Collection within K Steps Medium
Solution
•
Longest Subarray with Only Two Distinct Values Medium
Solution
•
Shortest Subarray to Remove to Make Array Sorted Medium
Solution