Solutions & Explanations

Browse 4,029+ detailed solutions with multiple approaches, code in Python, Java, C++ and more.

4,029 Solutions961 Easy2102 Medium966 Hard

Title	Difficulty	Acceptance	Topics	Solution
451. Sort Characters By Frequency	Medium	75.8%	Bucket Sort Counting+4	Read
452. Minimum Number of Arrows to Burst Balloons	Medium	61.9%	Array Greedy+1	Read
453. Minimum Moves to Equal Array Elements	Medium	58.6%	Array Math	Read
454. 4Sum II	Medium	57.9%	Array Hash Table	Read
455. Assign Cookies	Easy	55.4%	Array Greedy+2	Read
456. 132 Pattern	Medium	34.6%	Array Binary Search+3	Read
457. Circular Array Loop	Medium	38.3%	Array Hash Table+1	Read
458. Poor Pigs	Hard	59.4%	Combinatorics Dynamic Programming+1	Read
459. Repeated Substring Pattern	Easy	48.6%	String String Matching	Read
460. LFU Cache	Hard	50.0%	Design Doubly-Linked List+2	Read
461. Hamming Distance	Easy	76.7%	Bit Manipulation	Read
462. Minimum Moves to Equal Array Elements II	Medium	62.2%	Array Math+1	Read
463. Island Perimeter	Easy	74.3%	Array Breadth-First Search+2	Read
464. Can I Win	Medium	31.7%	Bit Manipulation Bitmask+4	Read
465. Optimal Account Balancing	Hard	50.3%	Array Backtracking+3	Read
466. Count The Repetitions	Hard	36.0%	Dynamic Programming String	Read
467. Unique Substrings in Wraparound String	Medium	44.0%	Dynamic Programming String	Read
468. Validate IP Address	Medium	28.2%	String	Read
469. Convex Polygon	Medium	40.3%	Array Geometry+1	Read
470. Implement Rand10() Using Rand7()	Medium	46.4%	Math Probability and Statistics+2	Read
471. Encode String with Shortest Length	Hard	50.5%	Dynamic Programming String	Read
472. Concatenated Words	Hard	49.9%	Array Depth-First Search+3	Read
473. Matchsticks to Square	Medium	42.3%	Array Backtracking+3	Read
474. Ones and Zeroes	Medium	53.7%	Array Dynamic Programming+1	Read
475. Heaters	Medium	42.3%	Array Binary Search+2	Read
476. Number Complement	Easy	70.3%	Bit Manipulation	Read
477. Total Hamming Distance	Medium	55.3%	Array Bit Manipulation+1	Read
478. Generate Random Point in a Circle	Medium	43.8%	Geometry Math+2	Read
479. Largest Palindrome Product	Hard	39.6%	Enumeration Math	Read
480. Sliding Window Median	Hard	38.7%	Array Hash Table+2	Read
481. Magical String	Medium	56.0%	String Two Pointers	Read
482. License Key Formatting	Easy	46.4%	String	Read
483. Smallest Good Base	Hard	47.0%	Binary Search Math	Read
484. Find Permutation	Medium	67.0%	Array Greedy+2	Read
485. Max Consecutive Ones	Easy	66.0%	Array	Read
486. Predict the Winner	Medium	59.7%	Array Dynamic Programming+3	Read
487. Max Consecutive Ones II	Medium	52.0%	Array Dynamic Programming+1	Read
488. Zuma Game	Hard	29.4%	Breadth-First Search Dynamic Programming+3	Read
489. Robot Room Cleaner	Hard	77.9%	Backtracking Interactive	Read
490. The Maze	Medium	60.4%	Array Breadth-First Search+2	Read
491. Non-decreasing Subsequences	Medium	63.1%	Array Backtracking+2	Read
492. Construct the Rectangle	Easy	65.2%	Math	Read
493. Reverse Pairs	Hard	35.1%	Array Binary Indexed Tree+5	Read
494. Target Sum	Medium	52.6%	Array Backtracking+1	Read
495. Teemo Attacking	Easy	58.2%	Array Simulation	Read
496. Next Greater Element I	Easy	76.5%	Array Hash Table+2	Read
497. Random Point in Non-overlapping Rectangles	Medium	40.2%	Array Binary Search+5	Read
498. Diagonal Traverse	Medium	67.1%	Array Matrix+1	Read
499. The Maze III	Hard	52.3%	Array Breadth-First Search+6	Read
500. Keyboard Row	Easy	74.3%	Array Hash Table+1	Read

#451Medium

Sort Characters By Frequency

Bucket SortCountingHash Table+3

Acceptance: 75.8%

#452Medium

Minimum Number of Arrows to Burst Balloons

ArrayGreedySorting

Acceptance: 61.9%

#453Medium

Minimum Moves to Equal Array Elements

ArrayMath

Acceptance: 58.6%

#454Medium

4Sum II

ArrayHash Table

Acceptance: 57.9%

#455Easy

Assign Cookies

ArrayGreedySorting+1

Acceptance: 55.4%

#456Medium

132 Pattern

ArrayBinary SearchMonotonic Stack+2

Acceptance: 34.6%

#457Medium

Circular Array Loop

ArrayHash TableTwo Pointers

Acceptance: 38.3%

#458Hard

Poor Pigs

CombinatoricsDynamic ProgrammingMath

Acceptance: 59.4%

#459Easy

Repeated Substring Pattern

StringString Matching

Acceptance: 48.6%

#460Hard

LFU Cache

DesignDoubly-Linked ListHash Table+1

Acceptance: 50.0%

#461Easy

Hamming Distance

Bit Manipulation

Acceptance: 76.7%

#462Medium

Minimum Moves to Equal Array Elements II

ArrayMathSorting

Acceptance: 62.2%

#463Easy

Island Perimeter

ArrayBreadth-First SearchDepth-First Search+1

Acceptance: 74.3%

#464Medium

Can I Win

Bit ManipulationBitmaskDynamic Programming+3

Acceptance: 31.7%

#465Hard

Optimal Account Balancing

ArrayBacktrackingBit Manipulation+2

Acceptance: 50.3%

#466Hard

Count The Repetitions

Dynamic ProgrammingString

Acceptance: 36.0%

#467Medium

Unique Substrings in Wraparound String

Dynamic ProgrammingString

Acceptance: 44.0%

#468Medium

Validate IP Address

String

Acceptance: 28.2%

#469Medium

Convex Polygon

ArrayGeometryMath

Acceptance: 40.3%

#470Medium

Implement Rand10() Using Rand7()

MathProbability and StatisticsRandomized+1

Acceptance: 46.4%

#471Hard

Encode String with Shortest Length

Dynamic ProgrammingString

Acceptance: 50.5%

#472Hard

Concatenated Words

ArrayDepth-First SearchDynamic Programming+2

Acceptance: 49.9%

#473Medium

Matchsticks to Square

ArrayBacktrackingBit Manipulation+2

Acceptance: 42.3%

#474Medium

Ones and Zeroes

ArrayDynamic ProgrammingString

Acceptance: 53.7%

#475Medium

Heaters

ArrayBinary SearchSorting+1

Acceptance: 42.3%

#476Easy

Number Complement

Bit Manipulation

Acceptance: 70.3%

#477Medium

Total Hamming Distance

ArrayBit ManipulationMath

Acceptance: 55.3%

#478Medium

Generate Random Point in a Circle

GeometryMathRandomized+1

Acceptance: 43.8%

#479Hard

Largest Palindrome Product

EnumerationMath

Acceptance: 39.6%

#480Hard

Sliding Window Median

ArrayHash TableHeap (Priority Queue)+1

Acceptance: 38.7%

#481Medium

Magical String

StringTwo Pointers

Acceptance: 56.0%

#482Easy

License Key Formatting

String

Acceptance: 46.4%

#483Hard

Smallest Good Base

Binary SearchMath

Acceptance: 47.0%

#484Medium

Find Permutation

ArrayGreedyStack+1

Acceptance: 67.0%

#485Easy

Max Consecutive Ones

Array

Acceptance: 66.0%

#486Medium

Predict the Winner

ArrayDynamic ProgrammingGame Theory+2

Acceptance: 59.7%

#487Medium

Max Consecutive Ones II

ArrayDynamic ProgrammingSliding Window

Acceptance: 52.0%

#488Hard

Zuma Game

Breadth-First SearchDynamic ProgrammingMemoization+2

Acceptance: 29.4%

#489Hard

Robot Room Cleaner

BacktrackingInteractive

Acceptance: 77.9%

#490Medium

The Maze

ArrayBreadth-First SearchDepth-First Search+1

Acceptance: 60.4%

#491Medium

Non-decreasing Subsequences

ArrayBacktrackingBit Manipulation+1

Acceptance: 63.1%

#492Easy

Construct the Rectangle

Math

Acceptance: 65.2%

#493Hard

Reverse Pairs

ArrayBinary Indexed TreeBinary Search+4

Acceptance: 35.1%

#494Medium

Target Sum

ArrayBacktrackingDynamic Programming

Acceptance: 52.6%

#495Easy

Teemo Attacking

ArraySimulation

Acceptance: 58.2%

#496Easy

Next Greater Element I

ArrayHash TableMonotonic Stack+1

Acceptance: 76.5%

#497Medium

Random Point in Non-overlapping Rectangles

ArrayBinary SearchMath+4

Acceptance: 40.2%

#498Medium

Diagonal Traverse

ArrayMatrixSimulation

Acceptance: 67.1%

#499Hard

The Maze III

ArrayBreadth-First SearchDepth-First Search+5

Acceptance: 52.3%

#500Easy

Keyboard Row

ArrayHash TableString

Acceptance: 74.3%

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Master DSA with Step-by-Step Solutions

Each solution article on FleetCode breaks down the problem into multiple approaches, from brute force to optimal, with detailed explanations and code in Python, Java, C++ and more. Understanding why an approach works - not just copying code - is what separates candidates who clear interviews from those who don't.

How to Use These Solutions

Try the problem first: Spend at least 20 minutes before reading the solution
Read all approaches: Start from brute force to understand the problem fully, then study the optimized solution
Understand the complexity: Pay attention to time and space analysis for each approach
Code it yourself: After understanding the approach, close the solution and implement from memory
Revisit after a week: Spaced repetition helps retain problem-solving patterns