| 3396 | Minimum Number of Operations to Make Elements in Array Distinct | ArrayHash Table | Easy |
| 3397 | Maximum Number of Distinct Elements After Operations | ArrayGreedySorting | Medium |
| 3398 | Smallest Substring With Identical Characters I | ArrayBinary SearchEnumeration | Hard |
| 3399 | Smallest Substring With Identical Characters II | StringBinary Search | Hard |
| 3402 | Minimum Operations to Make Columns Strictly Increasing | ArrayGreedyMatrix | Easy |
| 3403 | Find the Lexicographically Largest String From the Box I | Two PointersStringEnumeration | Medium |
| 3404 | Count Special Subsequences | ArrayHash TableMath+1 | Medium |
| 3405 | Count the Number of Arrays with K Matching Adjacent Elements | MathCombinatorics | Hard |
| 3407 | Substring Matching Pattern | StringString Matching | Easy |
| 3408 | Design Task Manager | Hash TableDesignHeap (Priority Queue)+1 | Medium |
| 3409 | Longest Subsequence With Decreasing Adjacent Difference | ArrayDynamic Programming | Medium |
| 3410 | Maximize Subarray Sum After Removing All Occurrences of One Element | ArrayDynamic ProgrammingSegment Tree | Hard |
| 3411 | Maximum Subarray With Equal Products | ArrayMathSliding Window+2 | Easy |
| 3412 | Find Mirror Score of a String | Hash TableStringStack+1 | Medium |
| 3413 | Maximum Coins From K Consecutive Bags | ArrayBinary SearchGreedy+3 | Medium |
| 3414 | Maximum Score of Non-overlapping Intervals | ArrayBinary SearchDynamic Programming+1 | Hard |
| 3417 | Zigzag Grid Traversal With Skip | ArrayMatrixSimulation | Easy |
| 3418 | Maximum Amount of Money Robot Can Earn | ArrayDynamic ProgrammingMatrix | Medium |
| 3419 | Minimize the Maximum Edge Weight of Graph | Binary SearchDepth-First SearchBreadth-First Search+2 | Medium |
| 3420 | Count Non-Decreasing Subarrays After K Operations | ArrayStackSegment Tree+4 | Hard |
| 3421 | Find Students Who Improved | Database | Medium |
| 3423 | Maximum Difference Between Adjacent Elements in a Circular Array | Array | Easy |
| 3424 | Minimum Cost to Make Arrays Identical | ArrayGreedySorting | Medium |
| 3425 | Longest Special Path | ArrayHash TableTree+2 | Hard |
| 3426 | Manhattan Distances of All Arrangements of Pieces | MathCombinatorics | Hard |
| 3427 | Sum of Variable Length Subarrays | ArrayPrefix Sum | Easy |
| 3428 | Maximum and Minimum Sums of at Most Size K Subsequences | ArrayMathDynamic Programming+2 | Medium |
| 3429 | Paint House IV | ArrayDynamic Programming | Medium |
| 3430 | Maximum and Minimum Sums of at Most Size K Subarrays | ArrayMathStack+1 | Hard |
| 3432 | Count Partitions with Even Sum Difference | ArrayMathPrefix Sum | Easy |
| 3433 | Count Mentions Per User | ArrayMathSorting+1 | Medium |
| 3434 | Maximum Frequency After Subarray Operation | ArrayHash TableDynamic Programming+3 | Medium |
| 3435 | Frequencies of Shortest Supersequences | ArrayStringBit Manipulation+3 | Hard |
| 3436 | Find Valid Emails | Database | Easy |
| 3438 | Find Valid Pair of Adjacent Digits in String | Hash TableStringCounting | Easy |
| 3439 | Reschedule Meetings for Maximum Free Time I | ArrayGreedySliding Window | Medium |
| 3440 | Reschedule Meetings for Maximum Free Time II | ArrayGreedyEnumeration | Medium |
| 3441 | Minimum Cost Good Caption | StringDynamic Programming | Hard |
| 3442 | Maximum Difference Between Even and Odd Frequency I | Hash TableStringCounting | Easy |
| 3443 | Maximum Manhattan Distance After K Changes | Hash TableMathString+1 | Medium |
| 3444 | Minimum Increments for Target Multiples in an Array | ArrayMathDynamic Programming+3 | Hard |
| 3445 | Maximum Difference Between Even and Odd Frequency II | StringSliding WindowEnumeration+1 | Hard |
| 3446 | Sort Matrix by Diagonals | ArraySortingMatrix | Medium |
| 3447 | Assign Elements to Groups with Constraints | ArrayHash Table | Medium |
| 3448 | Count Substrings Divisible By Last Digit | StringDynamic Programming | Hard |
| 3449 | Maximize the Minimum Game Score | ArrayBinary SearchGreedy | Hard |
| 3451 | Find Invalid IP Addresses | Database | Hard |
| 3452 | Sum of Good Numbers | Array | Easy |
| 3453 | Separate Squares I | ArrayBinary Search | Medium |
| 3454 | Separate Squares II | ArrayBinary SearchSegment Tree+1 | Hard |