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[简体中文](./README.md) | English

- Tree and Graph: Lowest Common Ancestor (LCA); Disjoint-Set

- String: Prefix Tree (Trie); Suffix Tree

[0042.trapping-rain-water](./problems/42.trapping-rain-water.md):


- [0371.sum-of-two-integers](./problems/371.sum-of-two-integers.md)

- [0575.distribute-candies](./problems/575.distribute-candies.md)

- [0002. Add Two Numbers](./problems/2.addTwoNumbers.md)

- [0024. Swap Nodes In Pairs](./problems/24.swapNodesInPairs.md)

- [0029.divide-two-integers](./problems/29.divide-two-integers.md)

- [0031.next-permutation](./problems/31.next-permutation.md)

- [0039.combination-sum](./problems/39.combination-sum.md)

- [0040.combination-sum-ii](./problems/40.combination-sum-ii.md)

- [0046.permutations](./problems/46.permutations.md)

- [0049.group-anagrams](./problems/49.group-anagrams.md)

- [0055.jump-game](./problems/55.jump-game.md)

- [0056.merge-intervals](./problems/56.merge-intervals.md)

- [0075.sort-colors](./problems/75.sort-colors.md)

- [0078.subsets](./problems/78.subsets.md)

- [0079.word-search](./problems/79.word-search-en.md)

- [0091.decode-ways](./problems/91.decode-ways.md)

- [0092.reverse-linked-list-ii](./problems/92.reverse-linked-list-ii.md)

- [0094.binary-tree-inorder-traversal](./problems/94.binary-tree-inorder-traversal.md)

- [0102.binary-tree-level-order-traversal](./problems/102.binary-tree-level-order-traversal.md)

- [0103.binary-tree-zigzag-level-order-traversal](./problems/103.binary-tree-zigzag-level-order-traversal.md)

- [0113.path-sum-ii](./problems/113.path-sum-ii.md)

- [0131.palindrome-partitioning](./problems/131.palindrome-partitioning.md)

- [0139.word-break](./problems/139.word-break.md)

- [0144.binary-tree-preorder-traversal](./problems/144.binary-tree-preorder-traversal.md)

- [0201.bitwise-and-of-numbers-range](./problems/201.bitwise-and-of-numbers-range.md)

- [0208.implement-trie-prefix-tree](./problems/208.implement-trie-prefix-tree.md)

- [0209.minimum-size-subarray-sum](./problems/209.minimum-size-subarray-sum.md)

- [0230.kth-smallest-element-in-a-bst](./problems/230.kth-smallest-element-in-a-bst.md)

- [0236.lowest-common-ancestor-of-a-binary-tree](./problems/236.lowest-common-ancestor-of-a-binary-tree.md)

- [0238.product-of-array-except-self](./problems/238.product-of-array-except-self.md)

- [0240.search-a-2-d-matrix-ii](./problems/240.search-a-2-d-matrix-ii.md)

- [0279.perfect-squares](./problems/279.perfect-squares.md)

- [0322.coin-change](./problems/322.coin-change.md)

- [0328.odd-even-linked-list](./problems/328.odd-even-linked-list.md)

- [0334.increasing-triplet-subsequence](./problems/334.increasing-triplet-subsequence.md)

- [0365.water-and-jug-problem](./problems/365.water-and-jug-problem.md)

- [0416.partition-equal-subset-sum](./problems/416.partition-equal-subset-sum.md)

- [0445.add-two-numbers-ii](./problems/445.add-two-numbers-ii.md)

- [0454.4-sum-ii](./problems/454.4-sum-ii.md)

- [0460.lfu-cache](./problems/460.lfu-cache.md) 🆕

- [1168.optimize-water-distribution-in-a-village](./problems/1168.optimize-water-distribution-in-a-village-en.md) 🆕

- [Data Structure](./thinkings/basic-data-structure-en.md) (Drafts)

- [Bloom Filter](./thinkings/bloom-filter-en.md)

- [String Problems](./thinkings/string-problems-en.md)

Anki falshcards would be mainly two parts: the mappings from key points to problems; the mappings from problems to idea thinks, key points and code implementations.

- [project](https://github.com/azl397985856/leetcode/projects/1)

- [Complete Anki Flashcards](./assets/anki/)

- [Collection of String Problem](./todo/str/)

We're still on the early stage, so feedback from community is very welcome. For sake of reducing the costs of communication, I created some chat groups.

(Add this bot and reply "leetcode" to join the group.)

- If you have any ideas, [Issues](https://github.com/azl397985856/leetcode/issues) or chat in groups.