| 206 | Reverse Linked List | Linked ListRecursion | Easy |
| 217 | Contains Duplicate | ArrayHash TableSorting | Easy |
| 219 | Contains Duplicate II | ArrayHash TableSliding Window | Easy |
| 222 | Count Complete Tree Nodes | Binary SearchBit ManipulationTree+1 | Easy |
| 225 | Implement Stack using Queues | StackDesignQueue | Easy |
| 226 | Invert Binary Tree | TreeDepth-First SearchBreadth-First Search+1 | Easy |
| 228 | Summary Ranges | Array | Easy |
| 231 | Power of Two | MathBit ManipulationRecursion | Easy |
| 232 | Implement Queue using Stacks | StackDesignQueue | Easy |
| 234 | Palindrome Linked List | Linked ListTwo PointersStack+1 | Easy |
| 242 | Valid Anagram | Hash TableStringSorting | Easy |
| 257 | Binary Tree Paths | StringBacktrackingTree+2 | Easy |
| 258 | Add Digits | MathSimulationNumber Theory | Easy |
| 263 | Ugly Number | Math | Easy |
| 268 | Missing Number | ArrayHash TableMath+3 | Easy |
| 278 | First Bad Version | Binary SearchInteractive | Easy |
| 283 | Move Zeroes | ArrayTwo Pointers | Easy |
| 290 | Word Pattern | Hash TableString | Easy |
| 292 | Nim Game | MathBrainteaserGame Theory | Easy |
| 303 | Range Sum Query - Immutable | ArrayDesignPrefix Sum | Easy |
| 326 | Power of Three | MathRecursion | Easy |
| 338 | Counting Bits | Dynamic ProgrammingBit Manipulation | Easy |
| 342 | Power of Four | MathBit ManipulationRecursion | Easy |
| 344 | Reverse String | Two PointersString | Easy |
| 345 | Reverse Vowels of a String | Two PointersString | Easy |
| 349 | Intersection of Two Arrays | ArrayHash TableTwo Pointers+2 | Easy |
| 350 | Intersection of Two Arrays II | ArrayHash TableTwo Pointers+2 | Easy |
| 367 | Valid Perfect Square | MathBinary Search | Easy |
| 374 | Guess Number Higher or Lower | Binary SearchInteractive | Easy |
| 383 | Ransom Note | Hash TableStringCounting | Easy |
| 387 | First Unique Character in a String | Hash TableStringQueue+1 | Easy |
| 389 | Find the Difference | Hash TableStringBit Manipulation+1 | Easy |
| 392 | Is Subsequence | Two PointersStringDynamic Programming | Easy |
| 401 | Binary Watch | BacktrackingBit Manipulation | Easy |
| 404 | Sum of Left Leaves | TreeDepth-First SearchBreadth-First Search+1 | Easy |
| 405 | Convert a Number to Hexadecimal | MathStringBit Manipulation | Easy |
| 409 | Longest Palindrome | Hash TableStringGreedy | Easy |
| 412 | Fizz Buzz | MathStringSimulation | Easy |
| 414 | Third Maximum Number | ArraySorting | Easy |
| 415 | Add Strings | MathStringSimulation | Easy |
| 434 | Number of Segments in a String | String | Easy |
| 441 | Arranging Coins | MathBinary Search | Easy |
| 448 | Find All Numbers Disappeared in an Array | ArrayHash Table | Easy |
| 455 | Assign Cookies | ArrayTwo PointersGreedy+1 | Easy |
| 459 | Repeated Substring Pattern | StringString Matching | Easy |
| 461 | Hamming Distance | Bit Manipulation | Easy |
| 463 | Island Perimeter | ArrayDepth-First SearchBreadth-First Search+1 | Easy |
| 476 | Number Complement | Bit Manipulation | Easy |
| 482 | License Key Formatting | String | Easy |
| 485 | Max Consecutive Ones | Array | Easy |