index

Reviewed LeetCode Problems (for my personal reference)

• akmhmgc - 206. Reverse Linked List
  • 関数の名前は、呼んでいるときに中身を見ずに、入力から何が出てくるかが分かるといいです。
• akmhmgc - 104. Maximum Depth of Binary Tree
• akmhmgc - 102. Binary Tree Level Order Traversal
• Apo-Matchbox - 206. Reverse Linked List
• brood0783 - 141. Linked List Cycle
• carolina-museum 392. Is Subsequence
• carolina-museum 35. Search Insert Position
• chanseok-lim - 141. Linked List Cycle
  • When checking two objects are the same, is should be used instead of ==.
• eito2002 - Valid Anagram
  • Always use if block
    • Chromium Code Reviews - Issue 10973006
  • EBCDIC ではアルファベットの文字コードがアルファベット順になっておらず、このコードが正しく動かないようです。ただし、 ASCII 等、近年使用されているほとんどの文字コードでは、アルファベットの文字コードがアルファベット順になっており、かつ今回の実行環境もそのようになっているので、このコードが意図通り動きます。ここまで意識できているとよいと思います。
  • Use the prefix form (++i) of the increment and decrement operators unless you need postfix semantics.
    • “The prefix form is generally more readable, is never less efficient, and can be more efficient because it doesn’t need to make a copy of the value as it was before the operation.”
• garunitule - 387. First Unique Character in a String
  • “Changed in version 3.7: Dictionary order is guaranteed to be insertion order. This behavior was an implementation detail of CPython from 3.6.”
• garunitule - 560. Subarray Sum Equals K
• garunitule - 200. Number of Islands
  • Command Query Separation
  • Descriptive function/variable names
  • “個人的な感覚、union find は現実的には多くの人が知っているし、知らなくても書かれれば読めるんですが、しかし、知らない同僚がいたとしても別に動揺しないというラインだと思いますね。”
• garunitule - 695. Max Area of Island
• garunitule - 323. Number of Connected Components in an Undirected Graph
  • To avoid RecursionError: maximum recursion depth exceeded while pickling an object., it makes sense to create a stack myself to perform DFS.
• garunitule - 104. Maximum Depth of Binary Tree
  • Cyclomatic Complexity, great engineers always come up with a very simple solution
  • Top down vs Bottom up
• garunitule - 127. Word Ladder
  • Shortest path -> BFS
• garunitule - 111. Minimum Depth of Binary Tree
  • Search for the shallowest leaf node -> BFS
• garunitule - 617. Merge Two Binary Trees
  • bottom-up -> recursive approach
  • copy.deepcopy() can copy an entire tree that consists of TreeNode
• garunitule - 108. Convert Sorted Array to Binary Search Tree
  • Time complexity -> peak memory
• garunitule - 112. Path Sum
• garunitule - 102. Binary Tree Level Order Traversal
• garunitule - 103. Binary Tree Zigzag Level Order Traversal
• h1rosaka - 49. Group Anagrams
• h1rosaka - 108. Convert Sorted Array to Binary Search Tree
• h1rosaka - 102. Binary Tree Level Order Traversal
• h1rosaka - 53. Maximum Subarray
• Kazuryu0907 - 1. Two Sum
• Kazuryu0907 - 387. First Unique Character in a String
• Kazuryu0907 - 560. Subarray Sum Equals K
• nanae772 - 49. Group Anagrams
• nanae772 - 53. Maximum Subarray
• plushn - 1. Two Sum
• potrue - 3. Longest Substring Without Repeating Characters
• ryosuketc - 322. Coin Change
  • Memoization with functools.cache
  • Two means of dynamic programming: memoization and tabulation
• Ryotaro25 - 226. Invert Binary Tree
  • std::swap
  • Google Style Guide: Do not use using-directives (e.g., using namespace foo)
• shintaroyoshida20 - 217. Contains Duplicate
  • MDN - Array.prototype.sort()
    • “The time and space complexity of the sort cannot be guaranteed as it depends on the implementation.”
• shintaro1993 - 53. Maximum Subarray
• skypenguins - 206. Reverse Linked List
• tokuhirat - 322. Coin Change
  • TIL: math.isinf()
• tokuhirat - 3. Longest Substring Without Repeating Characters
• tshimosake - 98. Validate Binary Search Tree
  • BST in-order traversal -> ascending (or correctly ordered) numbers
• yamashita-ki - 15. 3Sum
• yosukekato165 - 141. Linked List Cycle
  • a != b is a sugar syntax of a.__ne__(b)