feat: 盛水问题，香蕉问题

README.md

@@ -16,6 +16,11 @@ leetcode 题解，记录自己的 leecode 解题之路。
 
 > 只有熟练掌握基础的数据结构与算法，才能对复杂问题迎刃有余
 
+## 食用说明
+
+- 经典题目的解析的目录部分，前面有🆕的代表是最新更新的
+- 将来会在这里更新anki卡片
+
 
 ## 精彩预告
 
@@ -79,6 +84,8 @@ leetcode 题解，记录自己的 leecode 解题之路。
 - [900.rle-iterator](./problems/900.rle-iterator.md)
 - [322.coin-change](./problems/322.coin-change.md)
 - [518.coin-change-2](./problems/518.coin-change-2.md)
+- 🆕 [11.container-with-most-water](./problems/11.container-with-most-water.md)
+- 🆕 [875.koko-eating-bananas](./problems/875.koko-eating-bananas.md)
 
 #### 困难难度
 

problems/11.container-with-most-water.md

+## 题目地址
+https://leetcode.com/problems/container-with-most-water/description/
+
+## 题目描述
+```
+Given n non-negative integers a1, a2, ..., an , where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis forms a container, such that the container contains the most water.
+
+Note: You may not slant the container and n is at least 2.
+```
+ 
+![11.container-with-most-water-question](../assets/problems/11.container-with-most-water-question.jpg)
+```
+
+The above vertical lines are represented by array [1,8,6,2,5,4,8,3,7]. In this case, the max area of water (blue section) the container can contain is 49.
+
+ 
+
+Example:
+
+Input: [1,8,6,2,5,4,8,3,7]
+Output: 49
+```
+
+## 思路
+符合直觉的解法是，我们可以对两两进行求解，计算可以承载的水量。 然后不断更新最大值，最后返回最大值即可。
+这种解法，需要两层循环，时间复杂度是O(n^2)
+
+eg:
+
+```js
+   // 这个解法比较暴力，效率比较低
+    // 时间复杂度是O(n^2)
+    let max = 0;
+    for(let i = 0; i < height.length; i++) {
+        for(let j = i + 1; j < height.length; j++) {
+            const currentArea = Math.abs(i - j) * Math.min(height[i], height[j]);
+            if (currentArea > max) {
+                max = currentArea;
+            }
+        }
+    }
+    return max;
+
+```
+
+> 这种符合直觉的解法有点像冒泡排序， 大家可以稍微类比一下
+
+那么有没有更加优的解法呢？我们来换个角度来思考这个问题，上述的解法是通过两两组合，这无疑是完备的，
+那我门是否可以先计算长度为n的面积，然后计算长度为n-1的面积，... 计算长度为1的面积。 这样去不断更新最大值呢？
+很显然这种解法也是完备的，但是似乎时间复杂度还是O(n ^ 2), 不要着急。
+
+考虑一下，如果我们计算n-1长度的面积的时候,是直接直接排除一半的结果的。
+
+如图：
+
+![11.container-with-most-water](../assets/problems/11.container-with-most-water.png)
+
+
+比如我们计算n面积的时候，假如左侧的线段高度比右侧的高度低，那么我们通过左移右指针来将长度缩短为n-1的做法是没有意义的，
+因为`新的形成的面积变成了(n-1) * heightOfLeft 这个面积一定比刚才的长度为n的面积nn * heightOfLeft 小`
+
+也就是说最大面积`一定是当前的面积或者通过移动短的线段得到`。
+## 关键点解析
+
+- 双指针优化时间复杂度
+
+
+## 代码
+
+```js
+/*
+ * @lc app=leetcode id=11 lang=javascript
+ *
+ * [11] Container With Most Water
+ *
+ * https://leetcode.com/problems/container-with-most-water/description/
+ *
+ * algorithms
+ * Medium (42.86%)
+ * Total Accepted:    344.3K
+ * Total Submissions: 790.1K
+ * Testcase Example:  '[1,8,6,2,5,4,8,3,7]'
+ *
+ * Given n non-negative integers a1, a2, ..., an , where each represents a
+ * point at coordinate (i, ai). n vertical lines are drawn such that the two
+ * endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together
+ * with x-axis forms a container, such that the container contains the most
+ * water.
+ * 
+ * Note: You may not slant the container and n is at least 2.
+ * 
+ * 
+ * 
+ * 
+ * 
+ * The above vertical lines are represented by array [1,8,6,2,5,4,8,3,7]. In
+ * this case, the max area of water (blue section) the container can contain is
+ * 49. 
+ * 
+ * 
+ * 
+ * Example:
+ * 
+ * 
+ * Input: [1,8,6,2,5,4,8,3,7]
+ * Output: 49
+ * 
+ */
+/**
+ * @param {number[]} height
+ * @return {number}
+ */
+var maxArea = function(height) {
+    if (!height || height.length <= 1) return 0;
+    
+    // 双指针来进行优化
+    // 时间复杂度是O(n)
+    let leftPos = 0;
+    let rightPos = height.length - 1;
+    let max = 0;
+    while(leftPos < rightPos) {
+        
+        const currentArea = Math.abs(leftPos - rightPos) * Math.min(height[leftPos] , height[rightPos]);
+        if (currentArea > max) {
+            max = currentArea;
+        }
+        // 更新小的
+        if (height[leftPos] < height[rightPos]) {
+            leftPos++;
+        } else { // 如果相等就随便了
+            rightPos--;
+        }
+    }
+
+    return max;
+};
+```
+

problems/875.koko-eating-bananas.md

+## 题目地址
+https://leetcode.com/problems/koko-eating-bananas/description/
+
+## 题目描述
+```
+Koko loves to eat bananas.  There are N piles of bananas, the i-th pile has piles[i] bananas.  The guards have gone and will come back in H hours.
+
+Koko can decide her bananas-per-hour eating speed of K.  Each hour, she chooses some pile of bananas, and eats K bananas from that pile.  If the pile has less than K bananas, she eats all of them instead, and won't eat any more bananas during this hour.
+
+Koko likes to eat slowly, but still wants to finish eating all the bananas before the guards come back.
+
+Return the minimum integer K such that she can eat all the bananas within H hours.
+
+ 
+
+Example 1:
+
+Input: piles = [3,6,7,11], H = 8
+Output: 4
+Example 2:
+
+Input: piles = [30,11,23,4,20], H = 5
+Output: 30
+Example 3:
+
+Input: piles = [30,11,23,4,20], H = 6
+Output: 23
+ 
+
+Note:
+
+1 <= piles.length <= 10^4
+piles.length <= H <= 10^9
+1 <= piles[i] <= 10^9
+
+```
+
+## 思路
+符合直觉的做法是，选择最大的堆的香蕉数，然后试一下能不能行，如果不行则直接返回上次计算的结果，
+如果行，我们减少1个香蕉，试试行不行，依次类推。计算出刚好不行的即可。这种解法的时间复杂度是O(n)。
+
+这道题如果能看出来是二分法解决，那么其实很简单。为什么它是二分问题呢？
+我这里画了个图，我相信你看了就明白了。
+
+![koko-eating-bananas](../assets/problems/koko-eating-bananas.png)
+
+## 关键点解析
+
+- 二分查找
+
+
+## 代码
+
+```js
+/*
+ * @lc app=leetcode id=875 lang=javascript
+ *
+ * [875] Koko Eating Bananas
+ *
+ * https://leetcode.com/problems/koko-eating-bananas/description/
+ *
+ * algorithms
+ * Medium (44.51%)
+ * Total Accepted:    11.3K
+ * Total Submissions: 24.8K
+ * Testcase Example:  '[3,6,7,11]\n8'
+ *
+ * Koko loves to eat bananas.  There are N piles of bananas, the i-th pile has
+ * piles[i] bananas.  The guards have gone and will come back in H hours.
+ * 
+ * Koko can decide her bananas-per-hour eating speed of K.  Each hour, she
+ * chooses some pile of bananas, and eats K bananas from that pile.  If the
+ * pile has less than K bananas, she eats all of them instead, and won't eat
+ * any more bananas during this hour.
+ * 
+ * Koko likes to eat slowly, but still wants to finish eating all the bananas
+ * before the guards come back.
+ * 
+ * Return the minimum integer K such that she can eat all the bananas within H
+ * hours.
+ * 
+ * 
+ * 
+ * 
+ * 
+ * 
+ * 
+ * Example 1:
+ * 
+ * 
+ * Input: piles = [3,6,7,11], H = 8
+ * Output: 4
+ * 
+ * 
+ * 
+ * Example 2:
+ * 
+ * 
+ * Input: piles = [30,11,23,4,20], H = 5
+ * Output: 30
+ * 
+ * 
+ * 
+ * Example 3:
+ * 
+ * 
+ * Input: piles = [30,11,23,4,20], H = 6
+ * Output: 23
+ * 
+ * 
+ * 
+ * 
+ * Note:
+ * 
+ * 
+ * 1 <= piles.length <= 10^4
+ * piles.length <= H <= 10^9
+ * 1 <= piles[i] <= 10^9
+ * 
+ * 
+ * 
+ * 
+ * 
+ */
+
+ function canEatAllBananas(piles, H, mid) {
+     let h = 0;
+     for(let pile of piles) {
+        h += Math.ceil(pile / mid);
+     }
+
+     return h <= H;
+ }
+/**
+ * @param {number[]} piles
+ * @param {number} H
+ * @return {number}
+ */
+var minEatingSpeed = function(piles, H) {
+    let lo = 1,
+    hi = Math.max(...piles);
+
+    while(lo <= hi) {
+        let mid = lo + ((hi - lo) >> 1);
+        if (canEatAllBananas(piles, H, mid)) {
+            hi = mid - 1;
+        } else {
+            lo = mid + 1;
+        }
+    }
+
+    return lo; //  不能选择hi
+};
+```
+