| idx | name | number | from | answer | difficulty | related topics | note |
|---|---|---|---|---|---|---|---|
| 1 | Get Maximum in Generated Array | 1646 | LeetCode | A | Easy | array, dp, simulation | 8m |
| 2 | Minimum Deletions to Make Character Frequencies Unique | 1647 | LeetCode | A | Medium | string, greedy, sorting | 40m |
| 3 | Sell Diminishing-Valued Colored Balls | 1648 | LeetCode | A | Medium | array, math, binary search, greedy, sorting, heap | 120m |
| 4 | Create Sorted Array through Instructions | 1649 | LeetCode | A | Hard | array, binary search, dvide and conquer, binary indexd tree, segment tree, merge sort, ordered set | x |
| 5 | Check If Two String Arrays are Equivalent | 1662 | LeetCode | A | Easy | array, string | 4m |
| 6 | Smallest String With A Given Numeric Value | 1663 | LeetCode | A | Medium | string, greedy | 10m |
| 7 | Ways to Make a Fair Array | 1664 | LeetCode | A | Medium | array, dp | 25m |
| 8 | Richest Customer Wealth | 1672 | LeetCode | A | Easy | array, matrix | 10m |
| 9 | Find the Most Competitive Subsequence | 1673 | LeetCode | A | Medium | array, stack, greedy, monotonic stack | 45m |
| 10 | Count of Matches in Tournament | 1688 | LeetCode | A | Easy | math, simulation | 5m |
| 11 | Partitioning Into Minimum Number Of Deci-Binary Numbers | 1689 | LeetCode | A | Medium | string, greedy | 2m |
| 12 | Two Out of Three | 2032 | LeetCode | A | Easy | array, hash table | 22m |
| 13 | Binary Search | 704 | LeetCode | A | array, binary search | Easy | 13m |
| 14 | Guess Number Higher or Lower | 374 | LeetCode | A | Easy | binary search, interactive | 19m |
| 15 | Contains Duplicate | 217 | LeetCode | A | array, hash table, sorting | Easy | 4m |
| 16 | Reorder Data in Log Files | 937 | LeetCode | A | Easy | array, string, sorting | 47m |
| 17 | Most Common Word | 819 | LeetCode | A | Easy | hash table, string, counting | 23m |
| 18 | Group Anagrams | 49 | LeetCode | A | Medium | hash table, string, sorting | 11m |
| 19 | Longest Palindromic Substring | 5 | LeetCode | A | Medium | string, dp | x |
| 20 | Two Sum | 1 | LeetCode | A | Easy | array, hash table | 18m |
| 21 | Number of Islands | 200 | LeetCode | A | Medium | array, depth-first search, breadth-first search, union find, matrix | 18m |
m: Time spent solving alone
x: Can't solved
!: Got help from the solution
?: Still don't understand the solution (should try again)