azl397985856
diff --git a/README.en.md b/README.en.md
@@ -128,7 +128,7 @@ The data structures mainly includes:
 - [0055.jump-game](./problems/55.jump-game.md) 🆕 
 - [0062.unique-paths](./problems/62.unique-paths.md )🆕 
 - [0075.sort-colors](./problems/75.sort-colors.md)
-- [0078.subsets](./problems/78.subsets.md) 🆕 
+- [0078.subsets](./problems/78.subsets.md) 
 - [0086.partition-list](./problems/86.partition-list.md)
 - [0090.subsets-ii](./problems/90.subsets-ii.md)
 - [0091.decode-ways](./problems/91.decode-ways.md) 🆕 
@@ -142,21 +142,23 @@ The data structures mainly includes:
 - [0152.maximum-product-subarray](./problems/152.maximum-product-subarray.md) 🆕  
 - [0199.binary-tree-right-side-view](./problems/199.binary-tree-right-side-view.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) 🆕 
+- [0208.implement-trie-prefix-tree](./problems/208.implement-trie-prefix-tree.md)
 - [0209.minimum-size-subarray-sum](./problems/209.minimum-size-subarray-sum.md) 🖊 
-- [0236.lowest-common-ancestor-of-a-binary-tree](./problems/236.lowest-common-ancestor-of-a-binary-tree.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)
 - [0309.best-time-to-buy-and-sell-stock-with-cooldown](./problems/309.best-time-to-buy-and-sell-stock-with-cooldown.md) 🆕 
 - [0322.coin-change](./problems/322.coin-change.md)
-- [0334.increasing-triplet-subsequence](./problems/334.increasing-triplet-subsequence.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) 🆕
-- [0494.target-sum](./problems/494.target-sum.md) 🆕
+- [0494.target-sum](./problems/494.target-sum.md)
 - [0518.coin-change-2](./problems/518.coin-change-2.md)
+- [0609.find-duplicate-file-in-system](./problems/609.find-duplicate-file-in-system.md) 🆕
 - [0875.koko-eating-bananas](./problems/875.koko-eating-bananas.md)
 - [0877.stone-game](./problems/877.stone-game.md)
 - [0887.super-egg-drop](./problems/887.super-egg-drop.md)
@@ -204,16 +206,6 @@ Latest updated flashcards (only lists the front page):
 
 ### Future Plans
 
-- [0494.target-sum](./todo/494.target-sum.js)
-
-- [0609.find-duplicate-file-in-system](./todo/609.find-duplicate-file-in-system.js)
-
-- [0010.regular-expression-matching](./todo/10.regular-expression-matching.js)
-
-- [0309.best-time-to-buy-and-sell-stock-with-cooldown](./todo/309.best-time-to-buy-and-sell-stock-with-cooldown.js)
-
-- [0365.water-and-jug-problem](./todo/365.water-and-jug-problem.js)
-
 - [Complete Anki Flashcards](./assets/anki/)
 
 - [Collection of String Problem](./todo/str/)

diff --git a/README.md b/README.md
@@ -116,7 +116,7 @@ leetcode 题解，记录自己的 leetcode 解题之路。
 - [0002. Add Two Numbers](./problems/2.addTwoNumbers.md)
 - [0003. Longest Substring Without Repeating Characters](./problems/3.longestSubstringWithoutRepeatingCharacters.md)
 - [0011.container-with-most-water](./problems/11.container-with-most-water.md)
-- [0015.3-sum](./problems/15.3-sum.md) 🆕
+- [0015.3-sum](./problems/15.3-sum.md)
 - [0019. Remove Nth Node From End of List](./problems/19.removeNthNodeFromEndofList.md)
 - [0024. Swap Nodes In Pairs](./problems/24.swapNodesInPairs.md)
 - [0039.combination-sum](./problems/39.combination-sum.md)
@@ -126,7 +126,7 @@ leetcode 题解，记录自己的 leetcode 解题之路。
 - [0055.jump-game](./problems/55.jump-game.md) 🆕 
 - [0062.unique-paths](./problems/62.unique-paths.md )🆕 
 - [0075.sort-colors](./problems/75.sort-colors.md)
-- [0078.subsets](./problems/78.subsets.md) 🆕 
+- [0078.subsets](./problems/78.subsets.md)
 - [0086.partition-list](./problems/86.partition-list.md)
 - [0090.subsets-ii](./problems/90.subsets-ii.md)
 - [0091.decode-ways](./problems/91.decode-ways.md) 🆕 
@@ -140,21 +140,23 @@ leetcode 题解，记录自己的 leetcode 解题之路。
 - [0152.maximum-product-subarray](./problems/152.maximum-product-subarray.md) 🆕  
 - [0199.binary-tree-right-side-view](./problems/199.binary-tree-right-side-view.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) 🆕 
+- [0208.implement-trie-prefix-tree](./problems/208.implement-trie-prefix-tree.md)
 - [0209.minimum-size-subarray-sum](./problems/209.minimum-size-subarray-sum.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)
 - [0309.best-time-to-buy-and-sell-stock-with-cooldown](./problems/309.best-time-to-buy-and-sell-stock-with-cooldown.md) 🆕 
 - [0322.coin-change](./problems/322.coin-change.md)
-- [0334.increasing-triplet-subsequence](./problems/334.increasing-triplet-subsequence.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) 🆕
-- [0494.target-sum](./problems/494.target-sum.md) 🆕
+- [0494.target-sum](./problems/494.target-sum.md)
 - [0518.coin-change-2](./problems/518.coin-change-2.md)
+- [0609.find-duplicate-file-in-system](./problems/609.find-duplicate-file-in-system.md) 🆕
 - [0875.koko-eating-bananas](./problems/875.koko-eating-bananas.md)
 - [0877.stone-game](./problems/877.stone-game.md)
 - [0887.super-egg-drop](./problems/887.super-egg-drop.md)
@@ -200,16 +202,6 @@ anki - 文件 - 导入 - 下拉格式选择“打包的 anki集合”，然后
 
 ### 计划
 
-- [0494.target-sum](./todo/494.target-sum.js)
-
-- [0609.find-duplicate-file-in-system](./todo/609.find-duplicate-file-in-system.js)
-
-- [0010.regular-expression-matching](./todo/10.regular-expression-matching.js)
-
-- [0309.best-time-to-buy-and-sell-stock-with-cooldown](./todo/309.best-time-to-buy-and-sell-stock-with-cooldown.js)
-
-- [0365.water-and-jug-problem](./todo/365.water-and-jug-problem.js)
-
 - [anki 卡片 完善](./assets/anki/)
 
 - [字符串类问题汇总](./todo/str/)

diff --git a/backlog/326.power-of-three.js b/backlog/326.power-of-three.js
@@ -46,6 +46,7 @@
  * @return {boolean}
  */
 var isPowerOfThree = function(n) {
+  // tag: 数论
   // let i = 0;
   // while(Math.pow(3, i) < n) {
   //     i++;
@@ -55,3 +56,4 @@ var isPowerOfThree = function(n) {
   // 巧用整除
   return n > 0 && Math.pow(3, 19) % n === 0;
 };
+// 扩展： 这个方法可以扩展到任意质数，合数则不行
diff --git a/problems/365.water-and-jug-problem.md b/problems/365.water-and-jug-problem.md
@@ -0,0 +1,123 @@
+
+## 题目地址
+https://leetcode.com/problems/water-and-jug-problem/description/
+
+## 题目描述
+
+```
+You are given two jugs with capacities x and y litres. There is an infinite amount of water supply available. You need to determine whether it is possible to measure exactly z litres using these two jugs.
+
+If z liters of water is measurable, you must have z liters of water contained within one or both buckets by the end.
+
+Operations allowed:
+
+Fill any of the jugs completely with water.
+Empty any of the jugs.
+Pour water from one jug into another till the other jug is completely full or the first jug itself is empty.
+Example 1: (From the famous "Die Hard" example)
+
+Input: x = 3, y = 5, z = 4
+Output: True
+Example 2:
+
+Input: x = 2, y = 6, z = 5
+Output: False
+
+```
+
+## 思路
+
+这是一道关于`数论`的题目，确切地说是关于`裴蜀定理`（英语：Bézout's identity）的题目。
+
+摘自wiki的定义：
+
+```
+对任意两个整数 a、b，设 d是它们的最大公约数。那么关于未知数  x和  y的线性丢番图方程（称为裴蜀等式）：
+
+ax+by=m
+
+有整数解  (x,y) 当且仅当  m是  d的整数倍。裴蜀等式有解时必然有无穷多个解。
+
+```
+
+因此这道题可以完全转化为`裴蜀定理`。
+
+## 关键点解析
+
+- 数论
+- 裴蜀定理
+
+## 代码
+```js
+
+
+/*
+ * @lc app=leetcode id=365 lang=javascript
+ *
+ * [365] Water and Jug Problem
+ *
+ * https://leetcode.com/problems/water-and-jug-problem/description/
+ *
+ * algorithms
+ * Medium (28.76%)
+ * Total Accepted:    27K
+ * Total Submissions: 93.7K
+ * Testcase Example:  '3\n5\n4'
+ *
+ * You are given two jugs with capacities x and y litres. There is an infinite
+ * amount of water supply available. You need to determine whether it is
+ * possible to measure exactly z litres using these two jugs.
+ *
+ * If z liters of water is measurable, you must have z liters of water
+ * contained within one or both buckets by the end.
+ *
+ * Operations allowed:
+ *
+ *
+ * Fill any of the jugs completely with water.
+ * Empty any of the jugs.
+ * Pour water from one jug into another till the other jug is completely full
+ * or the first jug itself is empty.
+ *
+ *
+ * Example 1: (From the famous "Die Hard" example)
+ *
+ *
+ * Input: x = 3, y = 5, z = 4
+ * Output: True
+ *
+ *
+ * Example 2:
+ *
+ *
+ * Input: x = 2, y = 6, z = 5
+ * Output: False
+ *
+ */
+/**
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ * @return {boolean}
+ */
+var canMeasureWater = function(x, y, z) {
+  if (x + y < z) return false;
+
+  if (z === 0) return true;
+
+  if (x === 0) return y === z;
+
+  if (y === 0) return x === z;
+
+  function GCD(a, b) {
+    let min = Math.min(a, b);
+    while (min) {
+      if (a % min === 0 && b % min === 0) return min;
+      min--;
+    }
+    return 1;
+  }
+
+  return z % GCD(x, y) === 0;
+};
+```
diff --git a/problems/494.target-sum.md b/problems/494.target-sum.md
@@ -54,7 +54,7 @@ target的总数一共有多少种，这是一道我们之前做过的题目，
 ## 关键点解析
 
 - 对元素进行分组，分组的依据是符号， 是`+` 或者 `-`
-- 通过数学公式推导可以简化我们的求解过程，这需要一点`数学知识和数学意志`
+- 通过数学公式推导可以简化我们的求解过程，这需要一点`数学知识和数学意识`
 
 ## 代码
 ```js
@@ -132,3 +132,7 @@ var findTargetSumWays = function(nums, S) {
   return sumCount(nums, (S + sum) >> 1);
 };
 ```
+
+## 扩展
+
+如果这道题目并没有限定所有的元素以及target都是正数怎么办？