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
1462. Course Schedule IV	Medium	60.4%	Breadth-First Search Depth-First Search+2	Read
1465. Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts	Medium	41.1%	Array Greedy+1	Read
1466. Reorder Routes to Make All Paths Lead to the City Zero	Medium	65.7%	Breadth-First Search Depth-First Search+1	Read
1468. Calculate Salaries	Medium	78.4%	Database	Read
1471. The k Strongest Values in an Array	Medium	62.6%	Array Sorting+1	Read
1472. Design Browser History	Medium	78.3%	Array Data Stream+4	Read
1476. Subrectangle Queries	Medium	86.3%	Array Design+1	Read
1477. Find Two Non-overlapping Sub-arrays Each With Target Sum	Medium	49.5%	Array Binary Search+3	Read
1481. Least Number of Unique Integers after K Removals	Medium	63.8%	Array Counting+3	Read
1482. Minimum Number of Days to Make m Bouquets	Medium	56.9%	Array Binary Search	Read
1485. Clone Binary Tree With Random Pointer	Medium	81.2%	Binary Tree Breadth-First Search+3	Read
1487. Making File Names Unique	Medium	38.5%	Array Hash Table+1	Read
1488. Avoid Flood in The City	Medium	39.0%	Array Binary Search+3	Read
1490. Clone N-ary Tree	Medium	83.2%	Breadth-First Search Depth-First Search+2	Read
1492. The kth Factor of n	Medium	70.8%	Math Number Theory	Read
1493. Longest Subarray of 1's After Deleting One Element	Medium	71.1%	Array Dynamic Programming+1	Read
1497. Check If Array Pairs Are Divisible by k	Medium	46.2%	Array Counting+1	Read
1498. Number of Subsequences That Satisfy the Given Sum Condition	Medium	49.2%	Array Binary Search+2	Read
1500. Design a File Sharing System	Medium	41.7%	Data Stream Design+3	Read
1501. Countries You Can Safely Invest In	Medium	50.3%	Database	Read
1503. Last Moment Before All Ants Fall Out of a Plank	Medium	68.3%	Array Brainteaser+1	Read
1504. Count Submatrices With All Ones	Medium	71.0%	Array Dynamic Programming+3	Read
1506. Find Root of N-Ary Tree	Medium	78.4%	Bit Manipulation Depth-First Search+2	Read
1508. Range Sum of Sorted Subarray Sums	Medium	63.2%	Array Binary Search+2	Read
1509. Minimum Difference Between Largest and Smallest Value in Three Moves	Medium	59.2%	Array Greedy+1	Read
1513. Number of Substrings With Only 1s	Medium	57.4%	Math String	Read
1514. Path with Maximum Probability	Medium	65.4%	Array Graph+2	Read
1519. Number of Nodes in the Sub-Tree With the Same Label	Medium	55.5%	Breadth-First Search Counting+3	Read
1522. Diameter of N-Ary Tree	Medium	75.4%	Depth-First Search Tree	Read
1524. Number of Sub-arrays With Odd Sum	Medium	55.7%	Array Dynamic Programming+2	Read
1525. Number of Good Ways to Split a String	Medium	68.2%	Bit Manipulation Dynamic Programming+2	Read
1529. Minimum Suffix Flips	Medium	73.9%	Greedy String	Read
1530. Number of Good Leaf Nodes Pairs	Medium	71.9%	Binary Tree Depth-First Search+1	Read
1532. The Most Recent Three Orders	Medium	68.6%	Database	Read
1533. Find the Index of the Large Integer	Medium	56.7%	Array Binary Search+1	Read
1535. Find the Winner of an Array Game	Medium	56.8%	Array Simulation	Read
1536. Minimum Swaps to Arrange a Binary Grid	Medium	70.1%	Array Greedy+1	Read
1538. Guess the Majority in a Hidden Array	Medium	68.8%	Array Interactive+1	Read
1540. Can Convert String in K Moves	Medium	37.6%	Hash Table String	Read
1541. Minimum Insertions to Balance a Parentheses String	Medium	53.5%	Greedy Stack+1	Read
1545. Find Kth Bit in Nth Binary String	Medium	73.7%	Recursion Simulation+1	Read
1546. Maximum Number of Non-Overlapping Subarrays With Sum Equals Target	Medium	49.4%	Array Greedy+2	Read
1549. The Most Recent Orders for Each Product	Medium	64.9%	Database	Read
1551. Minimum Operations to Make Array Equal	Medium	82.8%	Math	Read
1552. Magnetic Force Between Two Balls	Medium	72.6%	Array Binary Search+1	Read
1554. Strings Differ by One Character	Medium	40.0%	Hash Function Hash Table+2	Read
1555. Bank Account Summary	Medium	51.5%	Database	Read
1557. Minimum Number of Vertices to Reach All Nodes	Medium	81.6%	Graph	Read
1558. Minimum Numbers of Function Calls to Make Target Array	Medium	62.9%	Array Bit Manipulation+1	Read
1559. Detect Cycles in 2D Grid	Medium	63.2%	Array Breadth-First Search+3	Read

#1462Medium

Course Schedule IV

Breadth-First SearchDepth-First SearchGraph+1

Acceptance: 60.4%

#1465Medium

Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts

ArrayGreedySorting

Acceptance: 41.1%

#1466Medium

Reorder Routes to Make All Paths Lead to the City Zero

Breadth-First SearchDepth-First SearchGraph

Acceptance: 65.7%

#1468Medium

Calculate Salaries

Database

Acceptance: 78.4%

#1471Medium

The k Strongest Values in an Array

ArraySortingTwo Pointers

Acceptance: 62.6%

#1472Medium

Design Browser History

ArrayData StreamDesign+3

Acceptance: 78.3%

#1476Medium

Subrectangle Queries

ArrayDesignMatrix

Acceptance: 86.3%

#1477Medium

Find Two Non-overlapping Sub-arrays Each With Target Sum

ArrayBinary SearchDynamic Programming+2

Acceptance: 49.5%

#1481Medium

Least Number of Unique Integers after K Removals

ArrayCountingGreedy+2

Acceptance: 63.8%

#1482Medium

Minimum Number of Days to Make m Bouquets

ArrayBinary Search

Acceptance: 56.9%

#1485Medium

Clone Binary Tree With Random Pointer

Binary TreeBreadth-First SearchDepth-First Search+2

Acceptance: 81.2%

#1487Medium

Making File Names Unique

ArrayHash TableString

Acceptance: 38.5%

#1488Medium

Avoid Flood in The City

ArrayBinary SearchGreedy+2

Acceptance: 39.0%

#1490Medium

Clone N-ary Tree

Breadth-First SearchDepth-First SearchHash Table+1

Acceptance: 83.2%

#1492Medium

The kth Factor of n

MathNumber Theory

Acceptance: 70.8%

#1493Medium

Longest Subarray of 1's After Deleting One Element

ArrayDynamic ProgrammingSliding Window

Acceptance: 71.1%

#1497Medium

Check If Array Pairs Are Divisible by k

ArrayCountingHash Table

Acceptance: 46.2%

#1498Medium

Number of Subsequences That Satisfy the Given Sum Condition

ArrayBinary SearchSorting+1

Acceptance: 49.2%

#1500Medium

Design a File Sharing System

Data StreamDesignHash Table+2

Acceptance: 41.7%

#1501Medium

Countries You Can Safely Invest In

Database

Acceptance: 50.3%

#1503Medium

Last Moment Before All Ants Fall Out of a Plank

ArrayBrainteaserSimulation

Acceptance: 68.3%

#1504Medium

Count Submatrices With All Ones

ArrayDynamic ProgrammingMatrix+2

Acceptance: 71.0%

#1506Medium

Find Root of N-Ary Tree

Bit ManipulationDepth-First SearchHash Table+1

Acceptance: 78.4%

#1508Medium

Range Sum of Sorted Subarray Sums

ArrayBinary SearchSorting+1

Acceptance: 63.2%

#1509Medium

Minimum Difference Between Largest and Smallest Value in Three Moves

ArrayGreedySorting

Acceptance: 59.2%

#1513Medium

Number of Substrings With Only 1s

MathString

Acceptance: 57.4%

#1514Medium

Path with Maximum Probability

ArrayGraphHeap (Priority Queue)+1

Acceptance: 65.4%

#1519Medium

Number of Nodes in the Sub-Tree With the Same Label

Breadth-First SearchCountingDepth-First Search+2

Acceptance: 55.5%

#1522Medium

Diameter of N-Ary Tree

Depth-First SearchTree

Acceptance: 75.4%

#1524Medium

Number of Sub-arrays With Odd Sum

ArrayDynamic ProgrammingMath+1

Acceptance: 55.7%

#1525Medium

Number of Good Ways to Split a String

Bit ManipulationDynamic ProgrammingHash Table+1

Acceptance: 68.2%

#1529Medium

Minimum Suffix Flips

GreedyString

Acceptance: 73.9%

#1530Medium

Number of Good Leaf Nodes Pairs

Binary TreeDepth-First SearchTree

Acceptance: 71.9%

#1532Medium

The Most Recent Three Orders

Database

Acceptance: 68.6%

#1533Medium

Find the Index of the Large Integer

ArrayBinary SearchInteractive

Acceptance: 56.7%

#1535Medium

Find the Winner of an Array Game

ArraySimulation

Acceptance: 56.8%

#1536Medium

Minimum Swaps to Arrange a Binary Grid

ArrayGreedyMatrix

Acceptance: 70.1%

#1538Medium

Guess the Majority in a Hidden Array

ArrayInteractiveMath

Acceptance: 68.8%

#1540Medium

Can Convert String in K Moves

Hash TableString

Acceptance: 37.6%

#1541Medium

Minimum Insertions to Balance a Parentheses String

GreedyStackString

Acceptance: 53.5%

#1545Medium

Find Kth Bit in Nth Binary String

RecursionSimulationString

Acceptance: 73.7%

#1546Medium

Maximum Number of Non-Overlapping Subarrays With Sum Equals Target

ArrayGreedyHash Table+1

Acceptance: 49.4%

#1549Medium

The Most Recent Orders for Each Product

Database

Acceptance: 64.9%

#1551Medium

Minimum Operations to Make Array Equal

Math

Acceptance: 82.8%

#1552Medium

Magnetic Force Between Two Balls

ArrayBinary SearchSorting

Acceptance: 72.6%

#1554Medium

Strings Differ by One Character

Hash FunctionHash TableRolling Hash+1

Acceptance: 40.0%

#1555Medium

Bank Account Summary

Database

Acceptance: 51.5%

#1557Medium

Minimum Number of Vertices to Reach All Nodes

Graph

Acceptance: 81.6%

#1558Medium

Minimum Numbers of Function Calls to Make Target Array

ArrayBit ManipulationGreedy

Acceptance: 62.9%

#1559Medium

Detect Cycles in 2D Grid

ArrayBreadth-First SearchDepth-First Search+2

Acceptance: 63.2%

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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