Welcome to Charlesna Algorithm: https://leetcode.com/charlesna/
A journey of a thousand miles begins with one small step.
My conclusion and Java code for Leetcode.
Thanks to https://github.com/lzl124631x and https://github.com/wisdompeak.
Gitbook is also availble from https://app.gitbook.com/@chenketao007/s/leetcode.
| # | Title | Difficulty | Solution |
|---|---|---|---|
| 10 | Regular Expression Matching | Hard | Solution |
| 17 | Letter Combinations of a Phone Number | Medium | Solution |
| 25 | Reverse Nodes in k-Group | Hard | Solution |
| 32 | Longest Valid Parentheses | Hard | Solution |
| 39 | Combination Sum | Medium | Solution |
| 40 | Combination Sum II | Medium | Solution |
| 42 | Trapping Rain Water | Hard | Solution |
| 54 | Spiral Matrix | Medium | Solution |
| 60 | Permutation Sequence | Medium | Solution |
| 68 | Text Justification | Hard | Solution |
| 77 | Combinations | Medium | Solution |
| 84 | Largest Rectangle in Histogram | Hard | Solution |
| 92 | Reverse Linked List II | Medium | Solution |
| 117 | Populating Next Right Pointers in Each Node II | Medium | Solution |
| 124 | Binary Tree Maximum Path Sum | Hard | Solution |
| 126 | Word Ladder II | Hard | Solution |
| 133 | Clone Graph | Medium | Solution |
| 139 | Word Break | Medium | Solution |
| 148 | Sort List | Medium | Solution |
| 174 | Dungeon Game | Hard | Solution |
| 201 | Bitwise AND of Numbers Range | Medium | Solution |
| 212 | Word Search II | Hard | Solution |
| 213 | House Robber II | Medium | Solution |
| 216 | Combination Sum III | Medium | Solution |
| 221 | Maximal Square | Medium | Solution |
| 233 | Number of Digit One | Hard | Solution |
| 239 | Sliding Window Maximum | Hard | Solution |
| 241 | Different Ways to Add Parentheses | Medium | Solution |
| 254 | Factor Combinations | Medium | Solution |
| 260 | Single Number III | Medium | Solution |
| 264 | Ugly Number II | Medium | Solution |
| 285 | Inorder Successor in BST | Medium | Solution |
| 305 | Number of Islands II | Hard | Solution |
| 306 | Additive Number | Medium | Solution |
| 307 | Range Sum Query - Mutable | Medium | Solution |
| 312 | Burst Balloons | Hard | Solution |
| 316 | Remove Duplicate Letters | Hard | Solution |
| 347 | Top K Frequent Elements | Medium | Solution |
| 368 | Largest Divisible Subset | Medium | Solution |
| 371 | Sum of Two Integers | Easy | Solution |
| 377 | Combination Sum IV | Medium | Solution |
| 385 | Mini Parser | Medium | Solution |
| 401 | Binary Watch | Easy | Solution |
| 402 | Remove K Digits | Medium | Solution |
| 410 | Split Array Largest Sum | Hard | Solution |
| 448 | Find All Numbers Disappeared in an Array | Easy | Solution |
| 456 | 132 Pattern | Medium | Solution |
| 460 | LFU Cache | Hard | Solution |
| 474 | Ones and Zeroes | Medium | Solution |
| 476 | Number Complement | Easy | Solution |
| 494 | Target Sum | Medium | Solution |
| 523 | Continuous Subarray Sum | Medium | Solution |
| 525 | Contiguous Array | Medium | Solution |
| 526 | Beautiful Arrangement | Medium | Solution |
| 552 | Student Attendance Record II | Hard | Solution |
| 581 | Shortest Unsorted Continuous Subarray | Easy | Solution |
| 583 | Delete Operation for Two Strings | Medium | Solution |
| 611 | Valid Triangle Number | Medium | Solution |
| 664 | Strange Printer | Hard | Solution |
| 698 | Partition to K Equal Sum Subsets | Medium | Solution |
| 679 | 24 Game | Hard | Solution |
| 726 | Number of Atoms | Hard | Solution |
| 740 | Delete and Earn | Medium | Solution |
| 743 | Network Delay Time | Medium | Solution |
| 762 | Prime Number of Set Bits in Binary Representation | Easy | Solution |
| 763 | Partition Labels | Medium | Solution |
| 765 | Couples Holding Hands | Hard | Solution |
| 788 | Rotated Digits | Easy | Solution |
| 798 | Smallest Rotation with Highest Score | Hard | Solution |
| 801 | Minimum Swaps To Make Sequences Increasing | Medium | Solution |
| 803 | Bricks Falling When Hit | Hard | Solution |
| 805 | Split Array With Same Average | Hard | Solution |
| 813 | Largest Sum of Averages | Medium | Solution |
| 835 | Image Overlap | Medium | Solution |
| 837 | New 21 Game | Medium | Solution |
| 842 | Split Array into Fibonacci Sequence | Medium | Solution |
| 851 | Loud and Rich | Medium | Solution |
| 862 | Shortest Subarray with Sum at Least K | Hard | Solution |
| 886 | Possible Bipartition | Medium | Solution |
| 903 | Valid Permutations for DI Sequence | Hard | Solution |
| 913 | Cat and Mouse | Hard | Solution |
| 924 | Minimize Malware Spread | Hard | Solution |
| 931 | Minimum Falling Path Sum | Medium | Solution |
| 943 | Find the Shortest Superstring | Hard | Solution |
| 947 | Most Stones Removed with Same Row or Column | Medium | Solution |
| 956 | Tallest Billboard | Hard | Solution |
| 978 | Longest Turbulent Subarray | Medium | Solution |
| 990 | Satisfiability of Equality Equations | Medium | Solution |
| 996 | Number of Squareful Arrays | Hard | Solution |
| 1043 | Partition Array for Maximum Sum | Medium | Solution |
| 1062 | Longest Repeating Substring | Medium | Solution |
| 1067 | Digit Count in Range | Hard | Solution |
| 1092 | Shortest Common Supersequence | Hard | Solution |
| 1096 | Brace Expansion II | Hard | Solution |
| 1130 | Minimum Cost Tree From Leaf Values | Medium | Solution |
| 1235 | Maximum Profit in Job Scheduling | Hard | Solution |
| 1240 | Tiling a Rectangle with the Fewest Squares | Hard | Solution |
| 1267 | Count Servers that Communicate | Medium | Solution |
| 1277 | Count Square Submatrices with All Ones | Medium | Solution |
| 1278 | Palindrome Partitioning III | Hard | Solution |
| 1286 | Iterator for Combination | Medium | Solution |
| 1289 | Minimum Falling Path Sum II | Hard | Solution |
| 1301 | Number of Paths with Max Score | Hard | Solution |
| 1319 | Number of Operations to Make Network Connected | Medium | Solution |
| 1330 | Reverse Subarray To Maximize Array Value | Hard | Solution |
| 1335 | Minimum Difficulty of a Job Schedule | Hard | Solution |
| 1344 | Jump Game V | Hard | Solution |
| 1349 | Maximum Students Taking Exam | Hard | Solution |
| 1368 | Minimum Cost to Make at Least One Valid Path in a Grid | Hard | Solution |
| 1371 | Find the Longest Substring Containing Vowels in Even Counts | Medium | Solution |
| 1391 | Check if There is a Valid Path in a Grid | Medium | Solution |
| 1397 | Find All Good Strings | Hard | Solution |
| 1420 | Build Array Where You Can Find The Maximum Exactly K Comparisons | Hard | Solution |
| 1462 | Course Schedule IV | Medium | Solution |
| 1473 | Paint House III | Hard | Solution |
| 1483 | Kth Ancestor of a Tree Node | Hard | Solution |
| 1494 | Parallel Courses II | Hard | Solution |
| 1505 | Minimum Possible Integer After at Most K Adjacent Swaps On Digits | Hard | Solution |
| 1521 | Find a Value of a Mysterious Function Closest to Target | Hard | Solution |