Repository with my solutions to various LeetCode problems.
To solve these problems I use functions from Golang Standard Library where applicable...
My main focus is with these areas: Arrays, Hash Tables, Strings, Dynamic Programming.
Read this document for all tips and tricks that are useful for solving these problems.
🟩 Easy: 263
🟨 Medium: 40
| # | Title | Solution | Level |
|---|---|---|---|
| 1 | Two Sum | link | 🟩 |
| 3 | Longest Substring Without Repeating Characters | link | 🟨 |
| 7 | Reverse Integer | link | 🟨 |
| 9 | Palindrome Number | link | 🟩 |
| 13 | Roman to Integer | link | 🟩 |
| 14 | Longest Common Prefix | link | 🟩 |
| 20 | Valid Parentheses | link | 🟩 |
| 21 | Merge Two Sorted Lists | link | 🟩 |
| 26 | Remove Duplicates from Sorted Array | link | 🟩 |
| 27 | Remove Element | link | 🟩 |
| 28 | Find the Index of the First Occurrence in a String | link | 🟩 |
| 35 | Search Insert Position | link | 🟩 |
| 46 | Permutations | link | 🟩 |
| 58 | Length of Last Word | link | 🟩 |
| 66 | Plus One | link | 🟩 |
| 67 | Add Binary | link | 🟩 |
| 69 | Sqrt(x) | link | 🟩 |
| 70 | Climbing Stairs | link | 🟩 |
| 75 | Sort Colors | link | 🟨 |
| 78 | Subsets | link | 🟨 |
| 83 | Remove Duplicates from Sorted List | link | 🟩 |
| 88 | Merge Sorted Array | link | 🟩 |
| 94 | Binary Tree Inorder Traversal | link | 🟩 |
| 100 | Same Tree | link | 🟩 |
| 101 | Symmetric Tree | link | 🟩 |
| 104 | Maximum Depth of Binary Tree | link | 🟩 |
| 118 | Pascal's Triangle | link | 🟩 |
| 119 | Pascal's Triangle II | link | 🟩 |
| 121 | Best Time to Buy and Sell Stock | link | 🟩 |
| 125 | Valid Palindrome | link | 🟩 |
| 136 | Single Number | link | 🟩 |
| 151 | Reverse Words in a String | link | 🟨 |
| 167 | Two Sum II | link | 🟨 |
| 168 | Excel Sheet Column Title | link | 🟩 |
| 169 | Majority Element | link | 🟩 |
| 171 | Excel Sheet Column Number | link | 🟩 |
| 190 | Reverse Bits | link | 🟩 |
| 191 | Number of 1 Bits | link | 🟩 |
| 198 | House Robber | link | 🟩 |
| 205 | Isomorphic Strings | link | 🟩 |
| 206 | Reverse Linked List | link | 🟩 |
| 217 | Contains Duplicate | link | 🟩 |
| 219 | Contains Duplicate II | link | 🟩 |
| 228 | Summary Ranges | link | 🟩 |
| 242 | Valid Anagram | link | 🟩 |
| 257 | Binary Tree Paths | link | 🟩 |
| 258 | Add Digits | link | 🟩 |
| 268 | Missing Number | link | 🟩 |
| 283 | Move Zeroes | link | 🟩 |
| 290 | Word Pattern | link | 🟩 |
| 303 | Range Sum Query - Immutable | link | 🟩 |
| 338 | Counting Bits | link | 🟩 |
| 344 | Reverse String | link | 🟩 |
| 345 | Reverse Vowels of a String | link | 🟩 |
| 349 | Intersection of Two Arrays | link | 🟩 |
| 350 | Intersection of Two Arrays II | link | 🟩 |
| 383 | Ransom Note | link | 🟩 |
| 387 | First Unique Character in a String | link | 🟩 |
| 389 | Find the Difference | link | 🟩 |
| 392 | Is Subsequence | link | 🟩 |
| 401 | Binary Watch | link | 🟩 |
| 405 | Convert a Number to Hexadecimal | link | 🟩 |
| 412 | Fizz Buzz | link | 🟩 |
| 415 | Add Strings | link | 🟩 |
| 434 | Number of Segments in a String | link | 🟩 |
| 442 | Find All Duplicates in an Array | link | 🟩 |
| 448 | Find All Numbers Disappeared in an Array | link | 🟩 |
| 451 | Sort Characters By Frequency | link | 🟨 |
| 455 | Assign Cookies | link | 🟩 |
| 459 | Repeated Substring Pattern | link | 🟩 |
| 463 | Island Perimeter | link | 🟩 |
| 476 | Number Complement | link | 🟩 |
| 482 | License Key Formatting | link | 🟩 |
| 485 | Max Consecutive Ones | link | 🟩 |
| 500 | Keyboard Row | link | 🟩 |
| 509 | Fibonacci Number | link | 🟩 |
| 520 | Detect Capital | link | 🟩 |
| 520 | Detect Capital | link | 🟩 |
| 535 | Encode and Decode TinyURL | link | 🟨 |
| 551 | Student Attendance Record I | link | 🟩 |
| 557 | Reverse Words in a String III | link | 🟩 |
| 599 | Minimum Index Sum of Two Lists | link | 🟩 |
| 657 | Robot Return to Origin | link | 🟩 |
| 682 | Baseball Game | link | 🟩 |
| 693 | Binary Number with Alternating Bits | link | 🟩 |
| 709 | To Lower Case | link | 🟩 |
| 724 | Find Pivot Index | link | 🟩 |
| 746 | Min Cost Climbing Stairs | link | 🟩 |
| 762 | Prime Number of Set Bits in Binary Representation | link | 🟩 |
| 771 | Jewels and Stones | link | 🟩 |
| 796 | Rotate String | link | 🟩 |
| 804 | Unique Morse Code Words | link | 🟩 |
| 806 | Number of Lines To Write String | link | 🟩 |
| 811 | Subdomain Visit Count | link | 🟨 |
| 819 | Most Common Word | link | 🟩 |
| 821 | Shortest Distance to a Character | link | 🟩 |
| 824 | Goat Latin | link | 🟩 |
| 830 | Positions of Large Groups | link | 🟩 |
| 832 | Flipping an Image | link | 🟩 |
| 844 | Backspace String Compare | link | 🟩 |
| 861 | Score After Flipping Matrix | link | 🟨 |
| 868 | Binary Gap | link | 🟩 |
| 884 | Uncommon Words from Two Sentences | link | 🟩 |
| 944 | Delete Columns to Make Sorted | link | 🟩 |
| 961 | N-Repeated Element in Size 2N Array | link | 🟩 |
| 1002 | Find Common Characters | link | 🟩 |
| 1047 | Remove All Adjacent Duplicates In String | link | 🟩 |
| 1051 | Height Checker | link | 🟩 |
| 1078 | Occurrences After Bigram | link | 🟩 |
| 1089 | Duplicate Zeros | link | 🟩 |
| 1108 | Defanging an IP Address | link | 🟩 |
| 1154 | Day of the Year | link | 🟩 |
| 1189 | Maximum Number of Balloons | link | 🟩 |
| 1207 | Unique Number of Occurrences | link | 🟩 |
| 1221 | Split a String in Balanced Strings | link | 🟩 |
| 1275 | Find Winner on a Tic Tac Toe Game | link | 🟩 |
| 1282 | Group the People Given the Group Size They Belong To | link | 🟨 |
| 1287 | Element Appearing More Than 25% In Sorted Array | link | 🟩 |
| 1304 | Find N Unique Integers Sum up to Zero | link | 🟩 |
| 1309 | Decrypt String from Alphabet to Integer Mapping | link | 🟩 |
| 1310 | XOR Queries of a Subarray | link | 🟨 |
| 1313 | Decompress Run-Length Encoded List | link | 🟩 |
| 1331 | Rank Transform of an Array | link | 🟩 |
| 1346 | Check If N and Its Double Exist | link | 🟩 |
| 1351 | Count Negative Numbers in a Sorted Matrix | link | 🟩 |
| 1360 | Number of Days Between Two Dates | link | 🟩 |
| 1365 | How Many Numbers Are Smaller Than the Current Number | link | 🟩 |
| 1380 | Lucky Numbers in a Matrix | link | 🟩 |
| 1381 | Design a Stack with Increment Operation | link | 🟨 |
| 1389 | Create Target Array in the Given Order | link | 🟩 |
| 1408 | String Matching in an Array | link | 🟩 |
| 1413 | Minimum Value to Get Positive Step by Step Sum | link | 🟩 |
| 1431 | Kids With the Greatest Number of Candies | link | 🟩 |
| 1436 | Destination City | link | 🟩 |
| 1455 | Check If a Word Occurs As a Prefix | link | 🟩 |
| 1470 | Shuffle the Array | link | 🟩 |
| 1476 | Subrectangle Queries | link | 🟨 |
| 1480 | Running Sum of 1d Array | link | 🟩 |
| 1486 | XOR Operation in an Array | link | 🟩 |
| 1496 | Path Crossing | link | 🟩 |
| 1507 | Reformat Date | link | 🟩 |
| 1512 | Number of Good Pairs | link | 🟩 |
| 1518 | Water Bottles | link | 🟩 |
| 1528 | Shuffle String | link | 🟩 |
| 1550 | Three Consecutive Odds | link | 🟩 |
| 1556 | Thousand Separator | link | 🟩 |
| 1561 | Maximum Number of Coins You Can Get | link | 🟨 |
| 1572 | Matrix Diagonal Sum | link | 🟩 |
| 1588 | Sum of All Odd Length Subarrays | link | 🟩 |
| 1592 | Rearrange Spaces Between Words | link | 🟩 |
| 1614 | Maximum Nesting Depth of the Parentheses | link | 🟩 |
| 1624 | Largest Substring Between Two Equal Characters | link | 🟩 |
| 1630 | Arithmetic Subarrays | link | 🟨 |
| 1637 | Widest Vertical Area Between Two Points Containing No Points | link | 🟩 |
| 1662 | Check If Two String Arrays are Equivalent | link | 🟩 |
| 1670 | Richest Customer Wealth | link | 🟩 |
| 1678 | Goal Parser Interpretation | link | 🟩 |
| 1684 | Count the Number of Consistent Strings | link | 🟩 |
| 1704 | Determine if String Halves Are Alike | link | 🟩 |
| 1720 | Decode XORed Array | link | 🟩 |
| 1742 | Maximum Number of Balls in a Box | link | 🟩 |
| 1768 | Merge Strings Alternately | link | 🟩 |
| 1769 | Minimum Number of Operations to Move All Balls to Each Box | link | 🟨 |
| 1773 | Count Items Matching a Rule | link | 🟩 |
| 1796 | Second Largest Digit in a String | link | 🟩 |
| 1805 | Number of Different Integers in a String | link | 🟩 |
| 1812 | Determine Color of a Chessboard Square | link | 🟩 |
| 1816 | Truncate Sentence | link | 🟩 |
| 1817 | Finidng the Users Active Minutes | link | 🟨 |
| 1827 | Minimum Operations to Make the Array Increasing | link | 🟩 |
| 1828 | Queries on Number of Points Inside a Circle | link | 🟨 |
| 1832 | Check if the Sentence Is Pangram | link | 🟩 |
| 1844 | Replace All Digits with Characters | link | 🟩 |
| 1854 | Maximum Population Year | link | 🟩 |
| 1859 | Sorting the Sentence | link | 🟩 |
| 1863 | Sum of All Subset XOR Totals | link | 🟩 |
| 1876 | Substrings of Size Three with Distinct Characters | link | 🟩 |
| 1877 | Minimize Maximum Pair Sum in Array | link | 🟨 |
| 1880 | Check if Word Equals Summation of Two Words | link | 🟩 |
| 1893 | Check if All the Integers in a Range Are Covered | link | 🟩 |
| 1910 | Remove All Occurrences of a Substring | link | 🟨 |
| 1913 | Maximum Product Difference Between Two Pairs | link | 🟩 |
| 1920 | Build Array from Permutation | link | 🟩 |
| 1929 | Concatenation of Array | link | 🟩 |
| 1941 | Check if All Characters Have Equal Number of Occurrences | link | 🟩 |
| 1967 | Number of Strings That Appear as Substrings in Word | link | 🟩 |
| 2000 | Reverse Prefix of Word | link | 🟩 |
| 2006 | Count Number of Pairs With Absolute Difference K | link | 🟩 |
| 2011 | Final Value of Variable After Performing Operations | link | 🟩 |
| 2037 | Minimum Number of Moves to Seat Everyone | link | 🟩 |
| 2079 | Watering Plants | link | 🟨 |
| 2085 | Count Common Words With One Occurrence | link | 🟩 |
| 2103 | Rings and Rods | link | 🟩 |
| 2114 | Maximum Number of Words Found in Sentences | link | 🟩 |
| 2119 | A Number After a Double Reversal | link | 🟩 |
| 2120 | Execution of All Suffix Instructions Staying in a Grid | link | 🟨 |
| 2129 | Capitalize the Title | link | 🟩 |
| 2149 | Rearrange Array Elements by Sign | link | 🟩 |
| 2160 | Minimum Sum of Four Digit Number After Splitting Digits | link | 🟩 |
| 2169 | Count Operations to Obtain Zero | link | 🟩 |
| 2185 | Counting Words With a Given Prefix | link | 🟩 |
| 2194 | Cells in a Range on an Excel Sheet | link | 🟩 |
| 2215 | Find the Difference of Two Arrays | link | 🟩 |
| 2221 | Find Triangular Sum of an Array | link | 🟨 |
| 2283 | Check if Number Has Equal Digit Count and Digit Value | link | 🟩 |
| 2309 | Greatest English Letter in Upper and Lower Case | link | 🟩 |
| 2315 | Count Asterisks | link | 🟩 |
| 2325 | Decode the Message | link | 🟩 |
| 2373 | Largest Local Values in a Matrix | link | 🟩 |
| 2390 | Removing Starts From a String | link | 🟨 |
| 2391 | Minimum Amount of Time to Collect Garbage | link | 🟨 |
| 2418 | Sort the People | link | 🟩 |
| 2428 | Maximum Sum of an Hourglass | link | 🟨 |
| 2433 | Find The Original Array of Prefix | link | 🟨 |
| 2442 | Count Number of Distinct Integer After Reverse Operations | link | 🟨 |
| 2446 | Determine if Two Events Have Conflict | link | 🟩 |
| 2451 | Odd String Difference | link | 🟩 |
| 2482 | Difference Between Ones and Zeros in Row and Column | link | 🟨 |
| 2485 | Find the Pivot Integer | link | 🟩 |
| 2496 | Maximum Value of a String in an Array | link | 🟩 |
| 2506 | Count Pairs of Similar Strings | link | 🟩 |
| 2540 | Minimum Common Value | link | 🟩 |
| 2545 | Sort the Students by Their Kth Score | link | 🟨 |
| 2553 | Separate the Digits in an Array | link | 🟩 |
| 2559 | Count Vowel Strings in Ranges | link | 🟨 |
| 2574 | Left and Right Sum Differences | link | 🟩 |
| 2586 | Count the Number of Vowel Strings in Range | link | 🟩 |
| 2595 | Number of Even and Odd Bits | link | 🟩 |
| 2610 | Convert an Array Into a 2D Array With Conditions | link | 🟨 |
| 2656 | Maximum Sum With Exactly K Elements | link | 🟩 |
| 2696 | Minimum String Length After Removing Substrings | link | 🟩 |
| 2716 | Minimize String Length | link | 🟩 |
| 2744 | Find Maximum Number of String Pairs | link | 🟩 |
| 2778 | Sum of Squares of Special Elements | link | 🟩 |
| 2785 | Sort Vowels in a String | link | 🟨 |
| 2788 | Split Strings by Separator | link | 🟩 |
| 2798 | Number of Employees Who Met the Target | link | 🟩 |
| 2810 | Faulty Keyboard | link | 🟩 |
| 2824 | Count Pairs Whose Sum is Less than Target | link | 🟩 |
| 2828 | Check if a String Is an Acronym of Words | link | 🟩 |
| 2843 | Count Symmetric Integers | link | 🟩 |
| 2848 | Points That Intersect With Cars | link | 🟩 |
| 2859 | Sum of Values at Indices With K Set Bits | link | 🟩 |
| 2864 | Maximum Odd Binary Number | link | 🟩 |
| 2894 | Divisible and Non-divisible Sums Difference | link | 🟩 |
| 2903 | Find Indices With Index and Value Difference I | link | 🟩 |
| 2908 | Minimum Sum of Mountain Triplets I | link | 🟩 |
| 2914 | Minimum Number of Changes to Make Binary String Beautiful | link | 🟨 |
| 2917 | Find the K-or of an Array | link | 🟩 |
| 2932 | Maximum Strong Pair XOR I | link | 🟩 |
| 2942 | Find Words Containing Character | link | 🟩 |
| 2960 | Count Tested Devices After Test Operations | link | 🟩 |
| 2974 | Minimum Number Game | link | 🟩 |
| 3005 | Count Elements With Maximum Frequency | link | 🟩 |
| 3019 | Number of Changing Keys | link | 🟩 |
| 3028 | Ant on the Boundary | link | 🟩 |
| 3033 | Modify the Matrix | link | 🟩 |
| 3046 | Split the Array | link | 🟩 |
| 3065 | Minimum Operations to Exceed Threshold Value I | link | 🟩 |
| 3074 | Apple Redistribution into Boxes | link | 🟩 |
| 3095 | Shortest Subarray With OR at Least K I | link | 🟩 |
| 3099 | Harshad Number | link | 🟩 |
| 3110 | Score of String | link | 🟩 |
| 3120 | Count the Number of Special Characters I | link | 🟩 |
| 3136 | Valid Word | link | 🟩 |
| 3151 | Special Array I | link | 🟩 |
| 3158 | Find the XOR of Numbers Which Appear Twice | link | 🟩 |
| 3162 | Find the Number of Good Pairs I | link | 🟩 |
| 3163 | String Compression III | link | 🟨 |
| 3168 | Minimum Number of Chairs in a Waiting Room | link | 🟩 |
| 3174 | Clear Digits | link | 🟩 |
| 3194 | Minimum Average of Smallest and Largest Elements | link | 🟩 |
| 3195 | Find the Minimum Area to Cover All Ones I | link | 🟨 |
| 3206 | Alternating Groups I | link | 🟩 |
| 3210 | Find the Encrypted String | link | 🟩 |
| 3216 | Lexicographically Smallest String After a Swap | link | 🟩 |
| 3226 | Number of Bit Changes to Make Two Integers Equal | link | 🟩 |
| 3232 | Find if Digit Game Can Be Won | link | 🟩 |
| 3242 | Design Neighbor Sum Service | link | 🟩 |
| 3248 | Snake in Matrix | link | 🟩 |
| 3258 | Count Substrings That Satisfy K-Constraint I | link | 🟩 |
| 3264 | Final Array State After K Multiplication Operations I | link | 🟩 |
| 3271 | Hash Divided String | link | 🟨 |
| 3289 | The Two Sneaky Numbers of Digitville | link | 🟩 |
| 3280 | Convert Date to Binary | link | 🟩 |
| 3285 | Find Indices of Stable Mountains | link | 🟩 |
| 3270 | Find the Key of the Numbers | link | 🟩 |
| 3274 | Check if Two Chessboard Squares Have the Same Color | link | 🟩 |
| 3300 | Minimum Element After Replacement With Digit Sum | link | 🟩 |
| 3304 | Find the K-th Character in String Game I | link | 🟩 |
| 3324 | Find the Sequence of Strings Appeared on the Screen | link | 🟨 |
| 3340 | Check Balanced String | link | 🟩 |
| 3354 | Make Array Elements Equal to Zero | link | 🟩 |
| 3360 | Stone Removal Game | link | 🟩 |
| 3370 | Smallest Number With All Set Bits | link | 🟩 |
| 3379 | Transformet Array | link | 🟩 |
| 3386 | Button with Longest Push Time | link | 🟩 |
| 3392 | Count Subarrays of Length Three With a Condition | link | 🟩 |
| 3396 | Minimum Number of Operations to Make Elements in Array Distinct | link | 🟩 |
| 3402 | Minimum Operations to Make Columns Strictly Increasing | link | 🟩 |
| 3407 | Substring Matching Pattern | link | 🟩 |
| 3412 | Find Mirror Score of a String | link | 🟨 |
| 3417 | Zigzag Grid Traversal With Skip | link | 🟩 |
| 3423 | Maximum Difference Between Adjacent Elements in a Circular Array | link | 🟩 |
Run golangci-lint command. There is a hidden configuration file for this tool inside root directory .golangci.yml.
$ golangci-lint --color always run --verbose ./...
For every problem I have used test file to verify the solution with bunch of test cases.
You can run these tests with command:
$ go test -v ./...
Many solutions also contain benchmarks.
$ go test -bench=. -benchmem ./1---Two-Sum
goos: linux
goarch: amd64
cpu: 13th Gen Intel(solutions/R) Core(solutions/TM) i7-13700K
Benchmark_twoSum_Iterations-24 100000000 13.83 ns/op 16 B/op 1 allocs/op
Benchmark_twoSum_Map-24 43644519 25.72 ns/op 16 B/op 1 allocs/op
PASS
