zdyxry / LeetCode

yiran's leetcode

yiran's leetcode

Bit Manipulation

Easy

• 0136 Single Number
• 0190 Reverse Bits
• 0191 Number Of 1 Bits
• 0231 Power Of Two
• 0342 Power Of Four
• 0371 Sum Of Two Integers
• 0389 Find The Difference
• 0401 Binary Watch
• 0405 Convert a Number to Hexadecimal
• 0461 Hamming Distance
• 0476 Number Complement
• 0477 Total Hamming Distance
• 0645 Set Mismatch
• 0693 Binary Number with Alternating Bits
• 0762 Prime Number of Set Bits in Binary Representation
• 0868 Binary Gap
• 1486 XOR Operation in an Array
• 1720 Decode XORed Array

Medium

• 0137 Single Number II
• 0187 Repeated DNA Sequences
• 0201 Bitwise AND of Numbers Range
• 0260 Single Number III
• 0318 Maximum Product of Word Lengths
• 0338 Counting Bits
• 0421 Maximum XOR of Two Numbers in an Array
• 1310 XOR Queries of a Subarray
• 1442 Count Triplets That Can Form Two Arrays of Equal XOR

Hard

• 1611 Minimum One Bit Operations to Make Integers Zero

Array

Easy

• 0001 Two Sum
• 0026 Remove Duplicates from Sorted Array
• 0027 Remove Element
• 0035 Search Insert Position
• 0053 Maximum Subarray
• 0066 Plus One
• 0088 Merge Sorted Array
• 0118 Pascal's Triangle
• 0119 Pascal's Triangle II
• 0121 Best Time to Buy and Sell Stock
• 0122 Best Time to Buy and Sell Stock II
• 0167 Two Sum II - Input array is sorted
• 0169 Majority Element
• 0189 Rotate Array
• 0217 Contains Duplicate
• 0219 Contains Duplicate II
• 0268 Missing Number
• 0283 Move Zeroes
• 0412 Fizz Buzz
• 0414 Third Maximum Number
• 0448 Find All Numbers Disappeared in an Array
• 0485 Max Consecutive Ones
• 0509 Fibonacci Number
• 0532 K-diff Pairs in an Array
• 0561 Array Partition I
• 0566 Reshape the Matrix
• 0581 Shortest Unsorted Continuous Subarray
• 0605 Can Place Flowers
• 0628 Maximum Product of Three Numbers
• 0643 Maximum Average Subarray I
• 0661 Image Smoother
• 0665 Non-decreasing Array
• 0674 Longest Continuous Increasing Subsequence
• 0697 Degree of an Array
• 0724 Find Pivot Index
• 0746 Min Cost Climbing Stairs
• 0766 Toeplitz Matrix
• 0830 Positions of Large Groups
• 0832 Flipping an Image
• 0849 Maximize Distance to Closest Person
• 0888 Fair Candy Swap
• 0896 Monotonic Array
• 0905 Sort Array By Parity
• 0922 Sort Array By Parity II
• 0941 Valid Mountain Array
• 0977 Squares of a Sorted Array
• 0985 Sum of Even Numbers After Queries
• 0989 Add to Array-Form of Integer
• 1018 Binary Prefix Divisible By 5
• 1089 Duplicate Zeros
• 1185 Day of the Week
• 1200 Minimum Absolute Difference
• 1217 Play with Chips
• 1252 Cells with Odd Values in a Matrix
• 1260 Shift 2D Grid
• 1266 Minimum Time Visiting All Points
• 1275 Find Winner on a Tic Tac Toe Game
• 1287 Element Appearing More Than 25% In Sorted Array
• 1304 Find N Unique Integers Sum up to Zero
• 1313 Decompress Run-Length Encoded List
• 1365 How Many Numbers Are Smaller Than the Current Number
• 1380 Lucky Numbers in a Matrix
• 1385 Find the Distance Value Between Two Arrays
• 1389 Create Target Array in the Given Order
• 1394 Find Lucky Integer in an Array
• 1399 Count Largest Group
• 1413 Minimum Value to Get Positive Step by Step Sum
• 1431 Kids With the Greatest Number of Candies
• 1450 Number of Students Doing Homework at a Given Time
• 1460 Make Two Arrays Equal by Reversing Sub-arrays
• 1464 Maximum Product of Two Elements in an Array
• 1470 Shuffle the Array
• 1475 Final Prices With a Special Discount in a Shop
• 1480 Running Sum of 1d Array
• 1491 Average Salary Excluding the Minimum and Maximum Salary
• 1502 Can Make Arithmetic Progression From Sequence
• 1508 Range Sum of Sorted Subarray Sums
• 1512 Number of Good Pairs
• 1534 Count Good Triplets
• 1539 Kth Missing Positive Number
• 1550 Three Consecutive Odds
• 1560 Most Visited Sector in a Circular Track
• 1566 Detect Pattern of Length M Repeated K or More Times
• 1572 Matrix Diagonal Sum
• 1582 Special Positions in a Binary Matrix
• 1588 Sum of All Odd Length Subarrays
• 1608 Special Array With X Elements Greater Than or Equal X
• 1619 Mean of Array After Removing Some Elements
• 1629 Slowest Key
• 1640 Check Array Formation Through Concatenation
• 1646 Get Maximum in Generated Array
• 1652 Defuse the Bomb
• 1656 Design an Ordered Stream
• 1672 Richest Customer Wealth
• 1700 Number of Students Unable to Eat Lunch
• 1732 Find the Highest Altitude
• 1742 Maximum Number of Balls in a Box
• 1748 Sum of Unique Elements
• 1752 Check if Array Is Sorted and Rotated
• 1758 Minimum Changes To Make Alternating Binary String
• 1779 Find Nearest Point That Has the Same X or Y Coordinate
• 1827 Minimum Operations to Make the Array Increasing
• 1848 Minimum Distance to the Target Element
• 1854 Maximum Population Year
• 1869 Longer Contiguous Segments of Ones than Zeros

Medium

• 0011 Container With Most Water
• 0015 3Sum
• 0016 3Sum Closest
• 0018 4Sum
• 0031 Next Permutation
• 0033 Search in Rotated Sorted Array
• 0034 Find First and Last Position of Element in Sorted Array
• 0039 Combination Sum
• 0040 Combination Sum II
• 0048 Rotate Image
• 0054 Spiral Matrix
• 0055 Jump Game
• 0056 Merge Intervals
• 0059 Spiral Matrix II
• 0062 Unique Paths
• 0063 Unique Paths II
• 0064 Minimum Path Sum
• 0073 Set Matrix Zeroes
• 0074 Search a 2D Matrix
• 0075 Sort Colors
• 0078 Subsets
• 0079 Word Search
• 0080 Remove Duplicates from Sorted Array II
• 0081 Search in Rotated Sorted Array II
• 0090 Subsets II
• 0105 Construct Binary Tree from Preorder and Inorder Traversal
• 0106 Construct Binary Tree from Inorder and Postorder Traversal
• 0120 Triangle
• 0152 Maximum Product Subarray
• 0153 Find Minimum in Rotated Sorted Array
• 0209 Minimum Size Subarray Sum
• 0216 Combination Sum III
• 0228 Summary Ranges
• 0229 Majority Element II
• 0238 Product of Array Except Self
• 0287 Find the Duplicate Number
• 0442 Find All Duplicates in an Array
• 0495 Teemo Attacking
• 0498 Diagonal Traverse
• 0565 Array Nesting
• 0769 Max Chunks To Make Sorted
• 0807 Max Increase to Keep City Skyline
• 0926 Flip String to Monotone Increasing
• 0950 Reveal Cards In Increasing Order
• 1052 Grumpy Bookstore Owner
• 1222 Queens That Can Attack the King
• 1233 Remove Sub-Folders from the Filesystem
• 1300 Sum of Mutated Array Closest to Target
• 1329 Sort the Matrix Diagonally
• 1337 The K Weakest Rows in a Matrix
• 1338 Reduce Array Size to The Half
• 1343 Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold
• 1366 Rank Teams by Votes
• 1375 Bulb Switcher III
• 1395 Count Number of Teams
• 1409 Queries on a Permutation With Key
• 1423 Maximum Points You Can Obtain from Cards
• 1424 Diagonal Traverse II
• 1437 Check If All 1's Are at Least Length K Places Away
• 1438 Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit
• 1465 Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts
• 1471 The k Strongest Values in an Array
• 1476 Subrectangle Queries
• 1488 Avoid Flood in The City
• 1493 Longest Subarray of 1's After Deleting One Element
• 1497 Check If Array Pairs Are Divisible by k
• 1503 Last Moment Before All Ants Fall Out of a Plank
• 1509 Minimum Difference Between Largest and Smallest Value in Three Moves
• 1524 Number of Sub-arrays With Odd Sum
• 1535 Find the Winner of an Array Game
• 1583 Count Unhappy Friends
• 1701 Average Waiting Time
• 1769 Minimum Number of Operations to Move All Balls to Each Box

Hash Table

Easy

• 0202 Happy Number
• 0204 Count Primes
• 0205 Isomorphic Strings
• 0242 Valid Anagram
• 0290 Word Pattern
• 0387 First Unique Character in a String
• 0409 Longest Palindrome
• 0438 Find All Anagrams in a String
• 0463 Island Perimeter
• 0500 Keyboard Row
• 0506 Relative Ranks
• 0575 Distribute Candies
• 0594 Longest Harmonious Subsequence
• 0599 Minimum Index Sum of Two Lists
• 0705 Design HashSet
• 0706 Design HashMap
• 0771 Jewels and Stones
• 0811 Subdomain Visit Count
• 0884 Uncommon Words from Two Sentences
• 0953 Verifying an Alien Dictionary
• 0961 N-Repeated Element in Size 2N Array
• 1002 Find Common Characters
• 1160 Find Words That Can Be Formed by Characters

Medium

• 0003 Longest Substring Without Repeating Characters
• 0036 Valid Sudoku
• 0049 Group Anagrams
• 0094 Binary Tree Inorder Traversal
• 0138 Copy List with Random Pointer
• 0347 Top K Frequent Elements
• 0451 Sort Characters By Frequency
• 0454 4Sum II
• 0525 Contiguous Array
• 0554 Brick Wall
• 0560 Subarray Sum Equals K
• 0648 Replace Words
• 0692 Top K Frequent Words
• 0718 Maximum Length of Repeated Subarray
• 0739 Daily Temperatures
• 0781 Rabbits in Forest
• 0930 Binary Subarrays With Sum
• 0939 Minimum Area Rectangle
• 0954 Array of Doubled Pairs
• 0974 Subarray Sums Divisible by K
• 1090 Largest Values From Labels
• 1418 Display Table of Food Orders in a Restaurant
• 1487 Making File Names Unique
• 1638 Count Substrings That Differ by One Character
• 1679 Max Number of K-Sum Pairs

String

Easy

• 0013 Roman to Integer
• 0014 Longest Common Prefix
• 0020 Valid Parentheses
• 0067 Add Binary
• 0344 Reverse String
• 0383 Ransom Note
• 0415 Add Strings
• 0434 Number of Segments in a String
• 0443 String Compression
• 0459 Repeated Substring Pattern
• 0482 License Key Formatting
• 0520 Detect Capital
• 0551 Student Attendance Record I
• 0557 Reverse Words in a String III
• 0657 Robot Return to Origin
• 0680 Valid Palindrome II
• 0696 Count Binary Substrings
• 0709. To Lower Case
• 0788 Rotated Digits
• 0796 Rotate String
• 0804 Unique Morse Code Words
• 0821 Shortest Distance to a Character
• 0859 Buddy Strings
• 0917 Reverse Only Letters
• 0925 Long Pressed Name
• 0929 Unique Email Addresses
• 0937 Reorder Data in Log Files
• 1108 Defanging an IP Address
• 1189 Maximum Number of Balloons
• 1309 Decrypt String from Alphabet to Integer Mapping
• 1370 Increasing Decreasing String
• 1374 Generate a String With Characters That Have Odd Counts
• 1408 String Matching in an Array
• 1417 Reformat The String
• 1422 Maximum Score After Splitting a String
• 1436 Destination City
• 1446 Consecutive Characters
• 1455 Check If a Word Occurs As a Prefix of Any Word in a Sentence
• 1496 Path Crossing
• 1556 Thousand Separator
• 1576 Replace All ?'s to Avoid Consecutive Repeating Characters
• 1592 Rearrange Spaces Between Words
• 1614 Maximum Nesting Depth of the Parentheses
• 1624 Largest Substring Between Two Equal Characters
• 1662 Check If Two String Arrays are Equivalent
• 1668 Maximum Repeating Substring
• 1678 Goal Parser Interpretation
• 1684 Count the Number of Consistent Strings
• 1694 Reformat Phone Number
• 1704 Determine if String Halves Are Alike
• 1736 Latest Time by Replacing Hidden Digits
• 1763 Longest Nice Substring
• 1768 Merge Strings Alternately
• 1773 Count Items Matching a Rule
• 1790 Check if One String Swap Can Make Strings Equal
• 1796 Second Largest Digit in a String
• 1805 Number of Different Integers in a String
• 1816 Truncate Sentence
• 1832 Check if the Sentence Is Pangram
• 1844 Replace All Digits with Characters
• 1876 Substrings of Size Three with Distinct Characters
• 1897 Redistribute Characters to Make All Strings Equal

Medium

• 0005 Longest Palindromic Substring
• 0006 ZigZag Conversion
• 0017 Letter Combinations of a Phone Number
• 0022 Generate Parentheses
• 0043 Multiply Strings
• 0093 Restore IP Addresses
• 0151 Reverse Words in a String
• 0227 Basic Calculator II
• 0539 Minimum Time Difference
• 0583 Delete Operation for Two Strings
• 0609 Find Duplicate File in System
• 0647 Palindromic Substrings
• 0678 Valid Parenthesis String
• 0767 Reorganize String
• 0791 Custom Sort String
• 0816 Ambiguous Coordinates
• 0842 Split Array into Fibonacci Sequence
• 0848 Shifting Letters
• 0856 Score of Parentheses
• 0890 Find and Replace Pattern
• 0916 Word Subsets
• 1138 Alphabet Board Path
• 1347 Minimum Number of Steps to Make Two Strings Anagram
• 1358 Number of Substrings Containing All Three Characters
• 1371 Find the Longest Substring Containing Vowels in Even Counts
• 1404 Number of Steps to Reduce a Number in Binary Representation to One
• 1410 HTML Entity Parser
• 1419 Minimum Number of Frogs Croaking
• 1432 Max Difference You Can Get From Changing an Integer
• 1433 Check If a String Can Break Another String
• 1451 Rearrange Words in a Sentence
• 1456 Maximum Number of Vowels in a Substring of Given Length
• 1461 Check If a String Contains All Binary Codes of Size K
• 1525 Number of Good Ways to Split a String
• 1529 Bulb Switcher IV
• 1540 Can Convert String in K Moves
• 1545 Find Kth Bit in Nth Binary String
• 1663 Smallest String With A Given Numeric Value
• 1839 Longest Substring Of All Vowels in Order

Linked List

Easy

• 0021 Merge Two Sorted Lists
• 0083 Remove Duplicates from Sorted List
• 0141 Linked List Cycle
• 0160 Intersection of Two Linked Lists
• 0203 Remove Linked List Elements
• 0206 Reverse Linked List
• 0234 Palindrome Linked List
• 0237 Delete Node in a Linked List
• 0707 Design Linked List
• 0876 Middle of the Linked List

Medium

• 0002 Add Two Numbers
• 0019 Remove Nth Node From End of List
• 0024 Swap Nodes in Pairs
• 0061 Rotate List
• 0082 Remove Duplicates from Sorted List II
• 0086 Partition List
• 0092 Reverse Linked List II
• 0109 Convert Sorted List to Binary Search Tree
• 0142 Linked List Cycle II
• 0143 Reorder List
• 0147 Insertion Sort List
• 0148 Sort List
• 0328 Odd Even Linked List
• 0445 Add Two Numbers II
• 0817 Linked List Components
• 1019 Next Greater Node In Linked List
• 1171 Remove Zero Sum Consecutive Nodes from Linked List
• 1367 Linked List in Binary Tree
• 1669 Merge In Between Linked Lists
• 1721 Swapping Nodes in a Linked List

Hard

• 0023 Merge k Sorted Lists
• 0025 Reverse Nodes in k-Group

Stack

Easy

• 0155 Min Stack
• 0225 Implement Stack using Queues
• 0232 Implement Queue using Stacks
• 0496 Next Greater Element I
• 0682 Baseball Game
• 0844 Backspace String Compare
• 1021 Remove Outermost Parentheses
• 1047 Remove All Adjacent Duplicates In String
• 1441 Build an Array With Stack Operations
• 1544 Make The String Great
• 1598 Crawler Log Folder

Medium

• 0071 Simplify Path
• 0103 Binary Tree Zigzag Level Order Traversal
• 0144 Binary Tree Preorder Traversal
• 0150 Evaluate Reverse Polish Notation
• 0331 Verify Preorder Serialization of a Binary Tree
• 0394 Decode String
• 0402 Remove K Digits
• 0456 132 Pattern
• 0503 Next Greater Element II
• 0735 Asteroid Collision
• 0880 Decoded String at Index
• 0901 Online Stock Span
• 0907 Sum of Subarray Minimums
• 0921 Minimum Add to Make Parentheses Valid
• 0946 Validate Stack Sequences
• 1130 Minimum Cost Tree From Leaf Values
• 1190 Reverse Substrings Between Each Pair of Parentheses
• 1209 Remove All Adjacent Duplicates in String II
• 1249 Minimum Remove to Make Valid Parentheses
• 1541 Minimum Insertions to Balance a Parentheses String
• 1642 Furthest Building You Can Reach
• 1673 Find the Most Competitive Subsequence

Heap

Easy

• 0703 Kth Largest Element in a Stream
• 1046 Last Stone Weight

Medium

• 0215 Kth Largest Element in an Array
• 0264 Ugly Number II
• 0313 Super Ugly Number
• 0373 Find K Pairs with Smallest Sums
• 0378 Kth Smallest Element in a Sorted Matrix
• 0659 Split Array into Consecutive Subsequences

Tree

Easy

• 0100 Same Tree
• 0101 Symmetric Tree
• 0104 Maximum Depth of Binary Tree
• 0107 Binary Tree Level Order Traversal II
• 0108 Convert Sorted Array to Binary Search Tree
• 0110 Balanced Binary Tree
• 0111 Minimum Depth of Binary Tree
• 0112 Path Sum
• 0226 Invert Binary Tree
• 0235 Lowest Common Ancestor of a Binary Search Tree
• 0257 Binary Tree Paths
• 0404 Sum of Left Leaves
• 0429 N-ary Tree Level Order Traversal
• 0437 Path Sum III
• 0501 Find Mode in Binary Search Tree
• 0530 Minimum Absolute Difference in BST
• 0538 Convert BST to Greater Tree
• 0543 Diameter of Binary Tree
• 0559 Maximum Depth of N-ary Tree
• 0563 Binary Tree Tilt
• 0572 Subtree of Another Tree
• 0589 N-ary Tree Preorder Traversal
• 0590 N-ary Tree Postorder Traversal
• 0617 Merge Two Binary Trees
• 0637 Average of Levels in Binary Tree
• 0653 Two Sum IV - Input is a BST
• 0669 Trim a Binary Search Tree
• 0687 Longest Univalue Path
• 0700 Search in a Binary Search Tree
• 0783 Minimum Distance Between BST Nodes
• 0872 Leaf-Similar Trees
• 0938 Range Sum of BST
• 0965 Univalued Binary Tree
• 0993 Cousins in Binary Tree
• 1022 Sum of Root To Leaf Binary Numbers

Medium

• 0095 Unique Binary Search Trees II
• 0096 Unique Binary Search Trees
• 0098 Validate Binary Search Tree
• 0102 Binary Tree Level Order Traversal
• 0113 Path Sum II
• 0114 Flatten Binary Tree to Linked List
• 0116 Populating Next Right Pointers in Each Node
• 0117 Populating Next Right Pointers in Each Node II
• 0129 Sum Root to Leaf Numbers
• 0145 Binary Tree Postorder Traversal
• 0173 Binary Search Tree Iterator
• 0199 Binary Tree Right Side View
• 0230 Kth Smallest Element in a BST
• 0236 Lowest Common Ancestor of a Binary Tree
• 0654 Maximum Binary Tree
• 0701 Insert into a Binary Search Tree
• 0814 Binary Tree Pruning
• 0894 All Possible Full Binary Trees
• 1008 Construct Binary Search Tree from Preorder Traversal
• 1026 Maximum Difference Between Node and Ancestor
• 1104 Path In Zigzag Labelled Binary Tree
• 1038 Binary Search Tree to Greater Sum Tree
• 1302 Deepest Leaves Sum
• 1305 All Elements in Two Binary Search Trees
• 1325 Delete Leaves With a Given Value
• 1372 Longest ZigZag Path in a Binary Tree
• 1379 Find a Corresponding Node of a Binary Tree in a Clone of That Tree
• 1382 Balance a Binary Search Tree
• 1600 Throne Inheritance
• 1609 Even Odd Tree

Binary Search

Easy

• 0069 Sqrt(x)
• 0278 First Bad Version
• 0367 Valid Perfect Square
• 0392 Is Subsequence
• 0704 Binary Search
• 0852 Peak Index in a Mountain Array

Medium

• 0240 Search a 2D Matrix II
• 0875 Koko Eating Bananas
• 0981 Time Based Key-Value Store
• 1111 Maximum Nesting Depth of Two Valid Parentheses Strings
• 1482 Minimum Number of Days to Make m Bouquets
• 1552 Magnetic Force Between Two Balls

Hard

• 0410 Split Array Largest Sum

Sort

Easy

• 0349 Intersection of Two Arrays
• 0350 Intersection of Two Arrays II
• 0976 Largest Perimeter Triangle
• 1030 Matrix Cells in Distance Order
• 1122 Relative Sort Array
• 1528 Shuffle String
• 1636 Sort Array by Increasing Frequency
• 1710 Maximum Units on a Truck

Medium

• 0179 Largest Number
• 1387 Sort Integers by The Power Value
• 1452 People Whose List of Favorite Companies Is Not a Subset of Another List
• 1481 Least Number of Unique Integers after K Removals
• 1498 Number of Subsequences That Satisfy the Given Sum Condition
• 1561 Maximum Number of Coins You Can Get
• 1630 Arithmetic Subarrays
• 1637 Widest Vertical Area Between Two Points Containing No Points

Math

Easy

• 0168 Excel Sheet Column Title
• 0171 Excel Sheet Column Number
• 0172 Factorial Trailing Zeroes
• 0263 Ugly Number
• 0441 Arranging Coins
• 0453 Minimum Moves to Equal Array Elements
• 0492 Construct the Rectangle
• 0504 Base 7
• 0728 Self Dividing Numbers
• 0883 Projection Area of 3D Shapes
• 0908 Smallest Range I
• 0942 DI String Match
• 1009 Complement of Base 10 Integer
• 1025 Divisor Game
• 1154 Day of the Year
• 1232 Check If It Is a Straight Line
• 1317 Convert Integer to the Sum of Two No-Zero Integers
• 1523 Count Odd Numbers in an Interval Range
• 1716 Calculate Money in Leetcode Bank
• 1822 Sign of the Product of an Array
• 1837 Sum of Digits in Base K

Medium

• 0029 Divide Two Integers
• 0050 Pow(x, n)
• 0343 Integer Break
• 0462 Minimum Moves to Equal Array Elements II
• 0553 Optimal Division
• 0754 Reach a Number
• 1227 Airplane Seat Assignment Probability
• 1344 Angle Between Hands of a Clock
• 1362 Closest Divisors
• 1363 Largest Multiple of Three
• 1390 Four Divisors
• 1401 Circle and Rectangle Overlapping
• 1447 Simplified Fractions
• 1492 The kth Factor of n
• 1513 Number of Substrings With Only 1s
• 1551 Minimum Operations to Make Array Equal
• 1685 Sum of Absolute Differences in a Sorted Array

Backtracking

Easy

• 1688 Count of Matches in Tournament

Medium

• 0089 Gray Code
• 0046 Permutations
• 0047 Permutations II
• 0060 Permutation Sequence
• 0077 Combinations
• 0131 Palindrome Partitioning
• 0784 Letter Case Permutation
• 1079. Letter Tile Possibilities
• 1219 Path with Maximum Gold
• 1286 Iterator for Combination
• 1415 The k-th Lexicographical String of All Happy Strings of Length n
• 1593 Split a String Into the Max Number of Unique Substrings

Dynamic Programming

Easy

• 0198 House Robber
• 0221 Maximal Square

Medium

• 0072 Edit Distance
• 0091 Decode Ways
• 0139 Word Break
• 0279 Perfect Squares
• 0309 Best Time to Buy and Sell Stock with Cooldown
• 0322 Coin Change
• 0375 Guess Number Higher or Lower II
• 0494 Target Sum
• 1048 Longest String Chain
• 1155 Number of Dice Rolls With Target Sum
• 1262 Greatest Sum Divisible by Three
• 1277 Count Square Submatrices with All Ones
• 1314 Matrix Block Sum
• 1546 Maximum Number of Non-Overlapping Subarrays With Sum Equals Target
• 1641 Count Sorted Vowel Strings
• 1664 Ways to Make a Fair Array

Depth-First Search

Easy

• 0897 Increasing Order Search Tree

Medium

• 0200 Number of Islands
• 0695 Max Area of Island
• 0797 All Paths From Source to Target
• 1110 Delete Nodes And Return Forest
• 1123 Lowest Common Ancestor of Deepest Leaves
• 1145 Binary Tree Coloring Game
• 1315 Sum of Nodes with Even-Valued Grandparent
• 1376 Time Needed to Inform All Employees
• 1443 Minimum Time to Collect All Apples in a Tree
• 1448 Count Good Nodes in Binary Tree
• 1457 Pseudo-Palindromic Paths in a Binary Tree
• 1519 Number of Nodes in the Sub-Tree With the Same Label
• 1530 Number of Good Leaf Nodes Pairs
• 1625 Lexicographically Smallest String After Applying Operations

Breadth-First Search

Medium

• 0127 Word Ladder
• 1466 Reorder Routes to Make All Paths Lead to the City Zero

Design

Easy

• 1603 Design Parking System

Medium

• 1348 Tweet Counts Per Frequency
• 1352 Product of the Last K Numbers
• 1357 Apply Discount Every n Orders
• 1381 Design a Stack With Increment Operation
• 1396 Design Underground System
• 1472 Design Browser History
• 1670 Design Front Middle Back Queue

Greedy

Easy

• 0455 Assign Cookies
• 0860 Lemonade Change
• 1221 Split a String in Balanced Strings
• 1403 Minimum Subsequence in Non-Increasing Order
• 1518 Water Bottles
• 1725 Number Of Rectangles That Can Form The Largest Square
• 1784 Check if Binary String Has at Most One Segment of Ones

Medium

• 0406 Queue Reconstruction by Height
• 0763 Partition Labels
• 0861 Score After Flipping Matrix
• 1094 Car Pooling
• 1282 Group the People Given the Group Size They Belong To
• 1353 Maximum Number of Events That Can Be Attended
• 1354 Construct Target Array With Multiple Sums
• 1386 Cinema Seat Allocation
• 1400 Construct K Palindrome Strings
• 1405 Longest Happy String
• 1414 Find the Minimum Number of Fibonacci Numbers Whose Sum Is K
• 1536 Minimum Swaps to Arrange a Binary Grid
• 1558 Minimum Numbers of Function Calls to Make Target Array
• 1567 Maximum Length of Subarray With Positive Product
• 1578 Minimum Deletion Cost to Avoid Repeating Letters
• 1605 Find Valid Matrix Given Row and Column Sums
• 1647 Minimum Deletions to Make Character Frequencies Unique
• 1653 Minimum Deletions to Make String Balanced
• 1657 Determine if Two Strings Are Close
• 1663 Smallest String With A Given Numeric Value
• 1689 Partitioning Into Minimum Number Of Deci-Binary Numbers
• 1702 Maximum Binary String After Change
• 1743 Restore the Array From Adjacent Pairs
• 1749 Maximum Absolute Sum of Any Subarray
• 1753 Maximum Score From Removing Stones
• 1764 Form Array by Concatenating Subarrays of Another Array
• 1774 Closest Dessert Cost

Trie

Medium

• 0677 Map Sum Pairs

Recursion

Easy

• 1137 N-th Tribonacci Number

Medium

• 0779 K-th Symbol in Grammar

Concurrency

Easy

• 1114 Print in Order

Graph

Medium

• 1161 Maximum Level Sum of a Binary Tree
• 1557 Minimum Number of Vertices to Reach All Nodes

Line Sweep

Medium

• 1288 Remove Covered Intervals

Two Pointers

Easy

• 1800 Maximum Ascending Subarray Sum

Medium

• 1695 Maximum Erasure Value