| 209 | Minimum Size Subarray Sum | ArrayBinary SearchSliding Window+1 | Medium |
| 210 | Course Schedule II | Depth-First SearchBreadth-First SearchGraph+1 | Medium |
| 211 | Design Add and Search Words Data Structure | StringDepth-First SearchDesign+1 | Medium |
| 212 | Word Search II | ArrayStringBacktracking+2 | Hard |
| 213 | House Robber II | ArrayDynamic Programming | Medium |
| 214 | Shortest Palindrome | StringRolling HashString Matching+1 | Hard |
| 215 | Kth Largest Element in an Array | ArrayDivide and ConquerSorting+2 | Medium |
| 216 | Combination Sum III | ArrayBacktracking | Medium |
| 217 | Contains Duplicate | ArrayHash TableSorting | Easy |
| 218 | The Skyline Problem | ArrayDivide and ConquerBinary Indexed Tree+4 | Hard |
| 219 | Contains Duplicate II | ArrayHash TableSliding Window | Easy |
| 220 | Contains Duplicate III | ArraySliding WindowSorting+2 | Hard |
| 221 | Maximal Square | ArrayDynamic ProgrammingMatrix | Medium |
| 222 | Count Complete Tree Nodes | Binary SearchBit ManipulationTree+1 | Easy |
| 223 | Rectangle Area | MathGeometry | Medium |
| 224 | Basic Calculator | MathStringStack+1 | Hard |
| 225 | Implement Stack using Queues | StackDesignQueue | Easy |
| 226 | Invert Binary Tree | TreeDepth-First SearchBreadth-First Search+1 | Easy |
| 227 | Basic Calculator II | MathStringStack | Medium |
| 228 | Summary Ranges | Array | Easy |
| 229 | Majority Element II | ArrayHash TableSorting+1 | Medium |
| 230 | Kth Smallest Element in a BST | TreeDepth-First SearchBinary Search Tree+1 | Medium |
| 231 | Power of Two | MathBit ManipulationRecursion | Easy |
| 232 | Implement Queue using Stacks | StackDesignQueue | Easy |
| 233 | Number of Digit One | MathDynamic ProgrammingRecursion | Hard |
| 234 | Palindrome Linked List | Linked ListTwo PointersStack+1 | Easy |
| 235 | Lowest Common Ancestor of a Binary Search Tree | TreeDepth-First SearchBinary Search Tree+1 | Medium |
| 236 | Lowest Common Ancestor of a Binary Tree | TreeDepth-First SearchBinary Tree | Medium |
| 237 | Delete Node in a Linked List | Linked List | Medium |
| 238 | Product of Array Except Self | ArrayPrefix Sum | Medium |
| 239 | Sliding Window Maximum | ArrayQueueSliding Window+2 | Hard |
| 240 | Search a 2D Matrix II | ArrayBinary SearchDivide and Conquer+1 | Medium |
| 241 | Different Ways to Add Parentheses | MathStringDynamic Programming+2 | Medium |
| 242 | Valid Anagram | Hash TableStringSorting | Easy |
| 257 | Binary Tree Paths | StringBacktrackingTree+2 | Easy |
| 258 | Add Digits | MathSimulationNumber Theory | Easy |
| 260 | Single Number III | ArrayBit Manipulation | Medium |
| 262 | Trips and Users | Database | Hard |
| 263 | Ugly Number | Math | Easy |
| 264 | Ugly Number II | Hash TableMathDynamic Programming+1 | Medium |
| 268 | Missing Number | ArrayHash TableMath+3 | Easy |
| 273 | Integer to English Words | MathStringRecursion | Hard |
| 274 | H-Index | ArraySortingCounting Sort | Medium |
| 275 | H-Index II | ArrayBinary Search | Medium |
| 278 | First Bad Version | Binary SearchInteractive | Easy |
| 279 | Perfect Squares | MathDynamic ProgrammingBreadth-First Search | Medium |
| 282 | Expression Add Operators | MathStringBacktracking | Hard |
| 283 | Move Zeroes | ArrayTwo Pointers | Easy |
| 284 | Peeking Iterator | ArrayDesignIterator | Medium |
| 287 | Find the Duplicate Number | ArrayTwo PointersBinary Search+1 | Medium |