Solutions & Explanations

Browse 4,030+ detailed solutions with multiple approaches, code in Python, Java, C++ and more.

4,030 Solutions961 Easy2102 Medium967 Hard

Title	Difficulty	Acceptance	Topics	Solution
1351. Count Negative Numbers in a Sorted Matrix	Easy	79.6%	Array Binary Search+1	Read
1352. Product of the Last K Numbers	Medium	62.9%	Array Data Stream+3	Read
1353. Maximum Number of Events That Can Be Attended	Medium	38.9%	Array Greedy+2	Read
1354. Construct Target Array With Multiple Sums	Hard	36.8%	Array Heap (Priority Queue)	Read
1355. Activity Participants	Medium	72.3%	Database	Read
1356. Sort Integers by The Number of 1 Bits	Easy	82.3%	Array Bit Manipulation+2	Read
1357. Apply Discount Every n Orders	Medium	66.1%	Array Design+1	Read
1358. Number of Substrings Containing All Three Characters	Medium	74.4%	Hash Table Sliding Window+1	Read
1359. Count All Valid Pickup and Delivery Options	Hard	64.9%	Combinatorics Dynamic Programming+1	Read
1360. Number of Days Between Two Dates	Easy	53.1%	Math String	Read
1361. Validate Binary Tree Nodes	Medium	43.8%	Binary Tree Breadth-First Search+4	Read
1362. Closest Divisors	Medium	64.3%	Math	Read
1363. Largest Multiple of Three	Hard	33.2%	Array Dynamic Programming+1	Read
1364. Number of Trusted Contacts of a Customer	Medium	74.9%	Database	Read
1365. How Many Numbers Are Smaller Than the Current Number	Easy	87.0%	Array Counting+2	Read
1366. Rank Teams by Votes	Medium	60.1%	Array Counting+3	Read
1367. Linked List in Binary Tree	Medium	52.1%	Binary Tree Depth-First Search+2	Read
1368. Minimum Cost to Make at Least One Valid Path in a Grid	Hard	70.9%	Array Breadth-First Search+4	Read
1369. Get the Second Most Recent Activity	Hard	67.5%	Database	Read
1370. Increasing Decreasing String	Easy	77.3%	Counting Hash Table+1	Read
1371. Find the Longest Substring Containing Vowels in Even Counts	Medium	75.7%	Bit Manipulation Hash Table+2	Read
1372. Longest ZigZag Path in a Binary Tree	Medium	67.0%	Binary Tree Depth-First Search+2	Read
1373. Maximum Sum BST in Binary Tree	Hard	48.9%	Binary Search Tree Binary Tree+3	Read
1374. Generate a String With Characters That Have Odd Counts	Easy	78.1%	String	Read
1375. Number of Times Binary String Is Prefix-Aligned	Medium	65.8%	Array	Read
1376. Time Needed to Inform All Employees	Medium	60.6%	Breadth-First Search Depth-First Search+1	Read
1377. Frog Position After T Seconds	Hard	38.8%	Breadth-First Search Depth-First Search+2	Read
1378. Replace Employee ID With The Unique Identifier	Easy	83.6%	Database	Read
1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Easy	85.9%	Binary Tree Breadth-First Search+2	Read
1380. Lucky Numbers in a Matrix	Easy	79.9%	Array Matrix	Read
1381. Design a Stack With Increment Operation	Medium	79.9%	Array Design+1	Read
1382. Balance a Binary Search Tree	Medium	86.3%	Binary Search Tree Binary Tree+4	Read
1383. Maximum Performance of a Team	Hard	47.6%	Array Greedy+2	Read
1384. Total Sales Amount by Year	Hard	61.0%	Database	Read
1385. Find the Distance Value Between Two Arrays	Easy	72.1%	Array Binary Search+2	Read
1386. Cinema Seat Allocation	Medium	56.8%	Array Bit Manipulation+2	Read
1387. Sort Integers by The Power Value	Medium	71.6%	Dynamic Programming Memoization+1	Read
1388. Pizza With 3n Slices	Hard	54.4%	Array Dynamic Programming+2	Read
1389. Create Target Array in the Given Order	Easy	86.6%	Array Simulation	Read
1390. Four Divisors	Medium	56.6%	Array Math	Read
1391. Check if There is a Valid Path in a Grid	Medium	64.5%	Array Breadth-First Search+3	Read
1392. Longest Happy Prefix	Hard	53.5%	Hash Function Rolling Hash+2	Read
1393. Capital Gain/Loss	Medium	85.3%	Database	Read
1394. Find Lucky Integer in an Array	Easy	75.5%	Array Counting+1	Read
1395. Count Number of Teams	Medium	70.1%	Array Binary Indexed Tree+2	Read
1396. Design Underground System	Medium	74.8%	Design Hash Table+1	Read
1397. Find All Good Strings	Hard	45.8%	Dynamic Programming String+1	Read
1398. Customers Who Bought Products A and B but Not C	Medium	72.3%	Database	Read
1399. Count Largest Group	Easy	74.7%	Hash Table Math	Read
1400. Construct K Palindrome Strings	Medium	68.6%	Counting Greedy+2	Read

#1351Easy

Count Negative Numbers in a Sorted Matrix

ArrayBinary SearchMatrix

Acceptance: 79.6%

#1352Medium

Product of the Last K Numbers

ArrayData StreamDesign+2

Acceptance: 62.9%

#1353Medium

Maximum Number of Events That Can Be Attended

ArrayGreedyHeap (Priority Queue)+1

Acceptance: 38.9%

#1354Hard

Construct Target Array With Multiple Sums

ArrayHeap (Priority Queue)

Acceptance: 36.8%

#1355Medium

Activity Participants

Database

Acceptance: 72.3%

#1356Easy

Sort Integers by The Number of 1 Bits

ArrayBit ManipulationCounting+1

Acceptance: 82.3%

#1357Medium

Apply Discount Every n Orders

ArrayDesignHash Table

Acceptance: 66.1%

#1358Medium

Number of Substrings Containing All Three Characters

Hash TableSliding WindowString

Acceptance: 74.4%

#1359Hard

Count All Valid Pickup and Delivery Options

CombinatoricsDynamic ProgrammingMath

Acceptance: 64.9%

#1360Easy

Number of Days Between Two Dates

MathString

Acceptance: 53.1%

#1361Medium

Validate Binary Tree Nodes

Binary TreeBreadth-First SearchDepth-First Search+3

Acceptance: 43.8%

#1362Medium

Closest Divisors

Math

Acceptance: 64.3%

#1363Hard

Largest Multiple of Three

ArrayDynamic ProgrammingGreedy

Acceptance: 33.2%

#1364Medium

Number of Trusted Contacts of a Customer

Database

Acceptance: 74.9%

#1365Easy

How Many Numbers Are Smaller Than the Current Number

ArrayCountingHash Table+1

Acceptance: 87.0%

#1366Medium

Rank Teams by Votes

ArrayCountingHash Table+2

Acceptance: 60.1%

#1367Medium

Linked List in Binary Tree

Binary TreeDepth-First SearchLinked List+1

Acceptance: 52.1%

#1368Hard

Minimum Cost to Make at Least One Valid Path in a Grid

ArrayBreadth-First SearchGraph+3

Acceptance: 70.9%

#1369Hard

Get the Second Most Recent Activity

Database

Acceptance: 67.5%

#1370Easy

Increasing Decreasing String

CountingHash TableString

Acceptance: 77.3%

#1371Medium

Find the Longest Substring Containing Vowels in Even Counts

Bit ManipulationHash TablePrefix Sum+1

Acceptance: 75.7%

#1372Medium

Longest ZigZag Path in a Binary Tree

Binary TreeDepth-First SearchDynamic Programming+1

Acceptance: 67.0%

#1373Hard

Maximum Sum BST in Binary Tree

Binary Search TreeBinary TreeDepth-First Search+2

Acceptance: 48.9%

#1374Easy

Generate a String With Characters That Have Odd Counts

String

Acceptance: 78.1%

#1375Medium

Number of Times Binary String Is Prefix-Aligned

Array

Acceptance: 65.8%

#1376Medium

Time Needed to Inform All Employees

Breadth-First SearchDepth-First SearchTree

Acceptance: 60.6%

#1377Hard

Frog Position After T Seconds

Breadth-First SearchDepth-First SearchGraph+1

Acceptance: 38.8%

#1378Easy

Replace Employee ID With The Unique Identifier

Database

Acceptance: 83.6%

#1379Easy

Find a Corresponding Node of a Binary Tree in a Clone of That Tree

Binary TreeBreadth-First SearchDepth-First Search+1

Acceptance: 85.9%

#1380Easy

Lucky Numbers in a Matrix

ArrayMatrix

Acceptance: 79.9%

#1381Medium

Design a Stack With Increment Operation

ArrayDesignStack

Acceptance: 79.9%

#1382Medium

Balance a Binary Search Tree

Binary Search TreeBinary TreeDepth-First Search+3

Acceptance: 86.3%

#1383Hard

Maximum Performance of a Team

ArrayGreedyHeap (Priority Queue)+1

Acceptance: 47.6%

#1384Hard

Total Sales Amount by Year

Database

Acceptance: 61.0%

#1385Easy

Find the Distance Value Between Two Arrays

ArrayBinary SearchSorting+1

Acceptance: 72.1%

#1386Medium

Cinema Seat Allocation

ArrayBit ManipulationGreedy+1

Acceptance: 56.8%

#1387Medium

Sort Integers by The Power Value

Dynamic ProgrammingMemoizationSorting

Acceptance: 71.6%

#1388Hard

Pizza With 3n Slices

ArrayDynamic ProgrammingGreedy+1

Acceptance: 54.4%

#1389Easy

Create Target Array in the Given Order

ArraySimulation

Acceptance: 86.6%

#1390Medium

Four Divisors

ArrayMath

Acceptance: 56.6%

#1391Medium

Check if There is a Valid Path in a Grid

ArrayBreadth-First SearchDepth-First Search+2

Acceptance: 64.5%

#1392Hard

Longest Happy Prefix

Hash FunctionRolling HashString+1

Acceptance: 53.5%

#1393Medium

Capital Gain/Loss

Database

Acceptance: 85.3%

#1394Easy

Find Lucky Integer in an Array

ArrayCountingHash Table

Acceptance: 75.5%

#1395Medium

Count Number of Teams

ArrayBinary Indexed TreeDynamic Programming+1

Acceptance: 70.1%

#1396Medium

Design Underground System

DesignHash TableString

Acceptance: 74.8%

#1397Hard

Find All Good Strings

Dynamic ProgrammingStringString Matching

Acceptance: 45.8%

#1398Medium

Customers Who Bought Products A and B but Not C

Database

Acceptance: 72.3%

#1399Easy

Count Largest Group

Hash TableMath

Acceptance: 74.7%

#1400Medium

Construct K Palindrome Strings

CountingGreedyHash Table+1

Acceptance: 68.6%

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Master DSA with Step-by-Step Solutions

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