15-3sum.md Separated Chinese and English solutions.

gazeldx · gazeldx · commit 00cad4e24ddd · 2025-01-23T09:41:05.000+08:00
diff --git a/en/1-1000/15-3sum.md b/en/1-1000/15-3sum.md
@@ -1,16 +1,11 @@
-# 15. 3Sum - LeetCode Solution
-LeetCode problem link: [15. 3Sum](https://leetcode.com/problems/3sum),
-[15. 三数之和](https://leetcode.cn/problems/3sum)
+# 15. 3Sum - LeetCode Solution Best Practice
+LeetCode link: [15. 3Sum](https://leetcode.com/problems/3sum), difficulty: **Medium**
 
-[中文题解](#中文题解)
-
-## LeetCode problem description
+## Description of "15. 3Sum"
 Given an integer array nums, return all the triplets `[nums[i], nums[j], nums[k]]` such that `i != j`, `i != k`, and `j != k`, and `nums[i] + nums[j] + nums[k] == 0`.
 
 Notice that the solution set must not contain duplicate triplets.
 
-Difficulty: **Medium**
-
 ### [Example 1]
 **Input**: `nums = [-1,0,1,2,-1,-4]`
 
@@ -43,6 +38,7 @@ Notice that the order of the output and the order of the triplets does not matte
 - `3 <= nums.length <= 3000`
 - `-10**5 <= nums[i] <= 10**5`
 
+### [Hints]
 <details>
   <summary>Hint 1</summary>
   So, we essentially need to find three numbers x, y, and z such that they add up to the given value. If we fix one of the numbers say x, we are left with the two-sum problem at hand!
@@ -59,8 +55,6 @@ Notice that the order of the output and the order of the triplets does not matte
 </details>
 
 ## Intuition
-[中文题解](#中文题解)
-
 1. The `sum` of three numbers equals `0`, which is equivalent to the `sum` of _two numbers_ equaling the _**negative** third number_.
 2. There are two options:
     1. First `determine two numbers` and `find the third number`
@@ -92,12 +86,6 @@ for (i = 0; i < nums.length; i++) {
 * Time: `O(N * N)`.
 * Space: `O(N)`.
 
-## Java
-```java
-// Welcome to create a PR to complete the code of this language, thanks!
-```
-
-
 ## Python
 ### Solution 1: Use Map (complex and slow)
 ```python
@@ -178,6 +166,11 @@ class Solution:
 // Welcome to create a PR to complete the code of this language, thanks!
 ```
 
+## Java
+```java
+// Welcome to create a PR to complete the code of this language, thanks!
+```
+
 ## JavaScript
 ```javascript
 // Welcome to create a PR to complete the code of this language, thanks!
@@ -198,77 +191,7 @@ class Solution:
 # Welcome to create a PR to complete the code of this language, thanks!
 ```
 
-## C
-```c
-// Welcome to create a PR to complete the code of this language, thanks!
-```
-
-## Kotlin
-```kotlin
-// Welcome to create a PR to complete the code of this language, thanks!
-```
-
-## Swift
-```swift
-// Welcome to create a PR to complete the code of this language, thanks!
+## C, Kotlin, Swift, Rust or other languages
 ```
-
-## Rust
-```rust
 // Welcome to create a PR to complete the code of this language, thanks!
 ```
-
-## Other languages
-```
-// Welcome to create a PR to complete the code of this language, thanks!
-```
-
-## 问题描述
-[15. 三数之和](https://leetcode.cn/problems/3sum), 难度: **中等**。
-
-给你一个整数数组 `nums` ，判断是否存在三元组 `[nums[i], nums[j], nums[k]]` 满足 `i != j`、`i != k` 且 `j != k` ，同时还满足 `nums[i] + nums[j] + nums[k] == 0` 。请你返回所有和为 `0` 且不重复的三元组。
-
-**注意**：答案中**不**可以包含**重复**的三元组。
-
-### [示例 1]
-**输入**: `nums = [-1,0,1,2,-1,-4]`
-
-**输出**: `[[-1,-1,2],[-1,0,1]]`
-
-**解释**:
-```
-nums[0] + nums[1] + nums[2] = (-1) + 0 + 1 = 0 。
-nums[1] + nums[2] + nums[4] = 0 + 1 + (-1) = 0 。
-nums[0] + nums[3] + nums[4] = (-1) + 2 + (-1) = 0 。
-不同的三元组是 [-1,0,1] 和 [-1,-1,2] 。
-注意，输出的顺序和三元组的顺序并不重要。
-```
-
-# 中文题解
-## 思路
-1. 三个数相加等于0，等同于`两个数相加的和`等于`负的第三个数`。
-2. 有两种方案可供选择：
-    1. 先定下两个数，查找第三个数
-    2. 先定下一个数，查找另外两个数
-3. 如果选择`方案1`，需要用到`Map`。因为需要对`nums`去重复；在`Map`中查找`第三个数`时，还需要避开已经定下的`两个数`，实现起来会比较麻烦。
-4. 如果选择`方案2`，查找另外两个数时，需要用到`two pointers`算法。
-5. 对于`方案1`，仅给出了`Python`示例代码。下文重点讲`方案2`。
-
-## 步骤
-1. 对`nums`进行排序。
-2. 遍历`nums`。
-3. 伪代码：
-```javascript
-for (i = 0; i < nums.length; i++) {
-   left = i + 1
-   right = nums.length - 1
-
-   while (left < right) {
-      if (condition1) {
-         left += 1
-      } else (condition2) {
-         right -= 1
-      }
-   }
-}
-```
diff --git a/en/3001-4000/unorganized.md b/en/3001-4000/unorganized.md
@@ -62,12 +62,37 @@ The improved way with a queue is commonly more efficient. Relaxing **All Edges**
 ## Others
 * Find all the prime numbers within 1000000.
 
-### Skipped problems/solutions
+## Skipped problems/solutions
 - 1047 https://leetcode.cn/problems/remove-all-adjacent-duplicates-in-string/
 - 150 https://leetcode.cn/problems/evaluate-reverse-polish-notation/
 - 239 https://leetcode.cn/problems/sliding-window-maximum/ tag `monotonic queue`
 - 347 https://leetcode.cn/problems/top-k-frequent-elements/ tag `heap sort`
-- 
-# Features
-* Add Google translate as a link. Link example: https://github-com.translate.goog/gazeldx/leetcode-solutions/blob/main/solutions/1-1000/122-best-time-to-buy-and-sell-stock-ii.md?_x_tr_sl=auto&_x_tr_tl=zh-CN&_x_tr_hl=en&_x_tr_pto=wapp
+
+### Binary Tree
+- 144 https://leetcode.cn/problems/binary-tree-preorder-traversal/
+- 94 https://leetcode.cn/problems/binary-tree-inorder-traversal/
+- 145 https://leetcode.cn/problems/binary-tree-postorder-traversal/
+- 102 https://leetcode.cn/problems/binary-tree-level-order-traversal/
+    - 107 https://leetcode.cn/problems/binary-tree-level-order-traversal-ii/
+    - 199 https://leetcode.cn/problems/binary-tree-right-side-view/
+    - 637 https://leetcode.cn/problems/average-of-levels-in-binary-tree/submissions/594783150/
+    - 429 https://leetcode.cn/problems/n-ary-tree-level-order-traversal/
+    - 515 https://leetcode.cn/problems/find-largest-value-in-each-tree-row/
+    - 116 https://leetcode.cn/problems/populating-next-right-pointers-in-each-node/
+    - 117 https://leetcode.cn/problems/populating-next-right-pointers-in-each-node-ii/
+    - 111 https://leetcode.cn/problems/minimum-depth-of-binary-tree/
+    
+- 104 https://leetcode.cn/problems/maximum-depth-of-binary-tree/
+- 226 https://leetcode.cn/problems/invert-binary-tree/
+- 101 https://leetcode.cn/problems/symmetric-tree/
+  - 100 https://leetcode.cn/problems/same-tree/description/
+  - 572 https://leetcode.cn/problems/subtree-of-another-tree/
+
+- 222 https://leetcode.cn/problems/count-complete-tree-nodes/
+- 110 https://leetcode.cn/problems/balanced-binary-tree/ 2 ways
+- 257 https://leetcode.cn/problems/binary-tree-paths/description/
+- 404 https://leetcode.cn/problems/sum-of-left-leaves/
+
+### Failed in 2 rounds
+- 222 https://leetcode.cn/problems/count-complete-tree-nodes/
 
diff --git a/zh/1-1000/15-3sum.md b/zh/1-1000/15-3sum.md
