I've been practicing Solidity programming by solving problems from DApp World.
As of now (31 Jan 2025), I solved 56 out of more than 59 problems, however, the site shows 54 for unknown reasons.
Below is the list of solved problmes in chronological order.
| Problem | Submission Date | Remarks |
|---|---|---|
| 1. Storage Smart Contract | 25 Nov 2024 13:12:05 | |
| 2. Calculate Factorial | 25 Nov 2024 15:19:43 | Calculated a factorial without recursion. |
| 3. Compare Strings | 25 Nov 2024 18:48:47 | Calculated the hash of two strings using keccak256 function. |
| 4. Owner Smart Contract | 27 Nov 2024 09:42:30 | |
| 5. Find Greatest | 27 Nov 2024 13:07:36 | |
| 6.Check Even Number | 27 Nov 2024 16:11:33 | |
| 9.Payment Channel | 5 Dec 2024 09:59:53 | Although the submission was passed, not sure whether the balances of the owner and the recipient are validated after closeChannel function is called. |
| 12.Simple Operations | 5 Dec 2024 14:49:40 | |
| 15.Vowel Removal | 5 Dec 2024 15:58:23 | When my solution was submitted, the last two test cases were hidden. |
| 18.Decimal to Binary - Easy | 5 Dec 2024 16:27:59 | When my solution was submitted, the last three test cases were hidden. |
| 24.Closest Prime Difference | 9 Dec 2024 09:21:54 | Didn't utilize the array of known prime numbers up to 271, since primeDifference should be a pure function.When my solution was submitted, the last three test cases were hidden. |
| 30.Fibonacci Sequence | 9 Dec 2024 10:41:50 | Calculated Fibonacci numbers without recursion. |
| 27.Palindrome Checker | 9 Dec 2024 15:47:25 | Printable ASCII characters are digits (0 - 9), uppercase letters (A - Z), lowercase letters (a - z), punctuation characters (!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~), and space ( ). |
| 33.Pythagoras Theorem | 9 Dec 2024 16:03:59 | |
| 36.Triangle Inequality | 9 Dec 2024 16:33:42 | |
| 49.GCD test | 9 Dec 2024 19:12:21 | |
| 39.LCM | 11 Dec 2024 09:59:51 | |
| 48.Gavin and Magic Array | 11 Dec 2024 10:17:40 | Although the submission was passed, not sure for hrs = 0 test cases. |
| 51.Gavin, Jack and abacus trick | 11 Dec 2024 14:29:04 | |
| 50.Gavin and smart wallet | 12 Dec 2024 09:57:15 | if accounts' balance were involved, addFunds/spendFunds functions should not have amount parameter. |
| 52.Gavin and the chocolate shop (Easy version) | 12 Dec 2024 10:31:58 | |
| 53.Gavin and the chocolate shop (Hard version) | 12 Dec 2024 11:00:57 | |
| 45.Dinesh and Gambling | 12 Dec 2024 15:37:55 | findSecondLargest function finds the largest and the second largest values by iterating the array only once. |
| 42.Jared and Maths Homework | 13 Dec 2024 13:32:13 | After submitting a solution, you may notice that parts of the problem statement are not correct. |
| 57.Diamond tracking (Easy version) | 13 Dec 2024 14:24:19 | |
| 55.Smart ranking (Easy version) | 13 Dec 2024 14:58:48 | |
| 59.Maximum profit | 13 Dec 2024 15:58:30 | I checked the submission, where the last two test cases are not for this problem, which is weird. |
| 56.Smart ranking (Hard version) | 14 Dec 2024 15:45:55 | |
| 58.Diamond tracking (Hard version) | 14 Dec 2024 18:39:47 | |
| 54.Smart Contract Solution for Buying Colors within Credit Limits | 15 Dec 2024 10:37:04 | |
| 21.ERC-20 Token | 16 Dec 2024 16:43:43 | Wrote ERC-20 token contract without using OpenZeppelin ERC20 contract, and wrote functions specified in the problem. |
| 17.Decimal to Binary - Hard | 16 Dec 2024 18:33:13 | When my solution was submitted, the last two test cases were hidden. |
| 32.Bus Ticket | 13 Jan 2025 13:28:32 | |
| 38.DAO Membership - Easy | 13 Jan 2025 13:56:43 | |
| 14.Cryptocurrency Round Trip | 13 Jan 2025 14:08:50 | |
| 37.DAO Membership - Hard | 13 Jan 2025 16:42:22 | |
| 41.Shipment Service (easy) | 13 Jan 2025 18:44:03 | |
| 40.Shipment Service (hard) | 13 Jan 2025 19:17:19 | |
| 44.Scholarship Credit System - Easy | 15 Jan 2025 16:19:07 | |
| 43.Scholarship Credit System - Hard | 16 Jan 2025 06:25:38 | |
| 8.DAO Voting | 16 Jan 2025 13:46:16 | Needed some trials and errors to clarify edge conditions and handle them appropriately. |
| 26.Automatic Lottery System - Easy | 16 Jan 2025 14:06:24 | Used a common way to generate pseudo random numbers with keccak256 function. |
| 25.Automatic Lottery System - Hard | 16 Jan 2025 15:30:46 | Used a common way to generate pseudo random numbers with keccak256 function. |
| 23.Token sale easy | 20 Jan 2025 15:38:04 | At the time when my solution was passed, I was the only one who passed all test cases (and thus got the best score). |
| 22.Token sale hard | 20 Jan 2025 16:54:22 | At the time when my solution was passed, I was the only one who passed all test cases (and thus got the best score). |
| 11.Crowdfunding - Easy | 20 Jan 2025 18:54:33 | |
| 10.Crowdfunding - Hard | 21 Jan 2025 13:35:34 | |
| 47.Gavin and the bookstore | 21 Jan 2025 15:36:41 | |
| 16.Auction | 22 Jan 2025 16:37:36 | |
| 7.Yeild Farming | 26 Jan 2025 11:33:37 | At the time when my solution was passed, I was the only one who passed all test cases (and thus got the best score). |
| 13.Decentralised Roulette | 27 Jan 2025 18:13:49 | |
| 46.Dapp World's got Talent | 29 Jan 2025 04:11:56 | At the time when my solution was passed, I was the only one who passed all test cases (and thus got the best score). |
| Calculate Fare | 29 Jan 2025 04:53:08 | |
| Club referral system | 29 Jan 2025 16:09:54 | |
| 35.Team Wallet - Easy | 30 Jan 2025 22:59:35 | At the time when my solution was passed, I was the only one who passed all test cases (and thus got the best score). |
| 34.Team Wallet - Hard | 31 Jan 2025 14:36:06 | At the time when my solution was passed, I was the only one who passed all test cases (and thus got the best score). |