[pull] master from wisdompeak:master

Design/2296.Design-a-Text-Editor/2296.Design-a-Text-Editor_v1.cpp

@@ -3,16 +3,13 @@ class TextEditor {
     list<char>::iterator iter;
 public:
     TextEditor() {
-        t.push_back('#');
         iter = t.begin();
     }
 
     void addText(string text) 
     {
         for (auto ch: text)
-        {
             t.insert(iter, ch);
-        }            
     }
 
     int deleteText(int k) 
@@ -24,7 +21,7 @@ class TextEditor {
             t.erase(iter2);
             k--;
             ret++;
-        }        
+        }
         return ret;
     }
 
@@ -35,36 +32,36 @@ class TextEditor {
             iter = prev(iter);
             k--;
         }
-        int p = 10;
-        while (iter!=t.begin() && p>0)
+        int p = 0;
+        while (iter!=t.begin() && p<10)
         {
             iter = prev(iter);
-            p--;
+            p++;
         }
         string ret;
-        for (int i=0; i<10-p; i++)
+        for (int i=0; i<p; i++)
         {
             ret.push_back(*iter);
             iter = next(iter);                
         }
-        return ret;            
+        return ret;
     }
 
     string cursorRight(int k) 
     {
-        while (*iter!='#' && k>0)
+        while (iter!=t.end() && k>0)
         {
             iter = next(iter);
             k--;
         }
-        int p = 10;
-        while (iter!=t.begin() && p>0)
+        int p = 0;
+        while (iter!=t.begin() && p<10)
         {
             iter = prev(iter);
-            p--;
+            p++;
         }
         string ret;
-        for (int i=0; i<10-p; i++)
+        for (int i=0; i<p; i++)
         {
             ret.push_back(*iter);
             iter = next(iter);                

Design/2296.Design-a-Text-Editor/Readme.md

@@ -0,0 +1,16 @@
+### 2296.Design-a-Text-Editor
+
+#### 解法1：链表
+本题需要有一种线性的数据结构，能有一个灵活的指针，可以o(1)地删除和添加指向的内部元素，并且依然可以o(1)的时间左移右移。显然这就是链表。
+
+C++里面自带链表结构：
+```cpp
+list<char>List;
+```
+该链表的迭代器就是指针
+```cpp
+list<char>::iterator iter;
+```
+
+#### 解法2：两个栈
+我们以指针为界，左边的部分放入一个栈，右边的部分放入一个栈。删除就意味着将弹出左边栈的顶部元素即可。打印的话，因为不超过10个字符，所以从栈顶拿出10个字符暂存下来再放回去就可以了。

Dynamic_Programming/2247.Maximum-Cost-of-Trip-With-K-Highways/2247.Maximum-Cost-of-Trip-With-K-Highways.cpp

@@ -0,0 +1,38 @@
+class Solution {
+public:
+    int maximumCost(int n, vector<vector<int>>& highways, int k) 
+    {
+        vector<vector<pair<int,int>>>next(n);
+        for (auto highway: highways)
+        {
+            int a = highway[0], b = highway[1], t = highway[2];
+            next[a].push_back({b,t});
+            next[b].push_back({a,t});
+        }
+
+        int ret = -1;
+        vector<vector<int>>dp(1<<n, vector<int>(n, INT_MIN));
+        for (int i=0; i<n; i++)
+            dp[1<<i][i] = 0;
+
+        for (int state = 0; state < (1<<n); state++)
+        {
+            for (int last=0; last<n; last++)
+            {
+                if (((state>>last)&1)==0) continue;
+                for (auto nxt: next[last])
+                {
+                    auto [j, t] = nxt;
+                    if ((state>>j)&1) continue;
+                    dp[state+(1<<j)][j] = max(dp[state+(1<<j)][j], dp[state][last]+t);
+                }                
+
+                if (__builtin_popcount(state)==k+1)
+                    ret = max(ret, dp[state][last]);
+            }
+        }
+
+        return ret;
+
+    }
+};

Dynamic_Programming/2247.Maximum-Cost-of-Trip-With-K-Highways/Readme.md

@@ -0,0 +1,9 @@
+### 2247.Maximum-Cost-of-Trip-With-K-Highways
+
+本题是说要找出一条最长的路径，恰能包含k+1个节点（起始点可以自由选择）。要求节点不能重复经过（自然边也不会重复经过）。
+
+这是一个经典的旅行商问题（TSP）。解法和```943.Find-the-Shortest-Superstring```一样。考虑到节点总数不超过15个，我们可以用二进制数state表示经过的节点的集合。令dp[state][last]表示走过了state所代表的节点集合、并且最后一站是节点last的情况下，所能得到的最优解。假设last与j相邻，且j不在state中，则有状态转移方程
+```cpp
+dp[state + (1<<j)][j] = dp[state][last] + cost[last][j]
+```
+最终考察所有含有k+1个节点的state，取其dp值的最大。

Dynamic_Programming/2291.Maximum-Profit-From-Trading-Stocks/2291.Maximum-Profit-From-Trading-Stocks.cpp

@@ -0,0 +1,16 @@
+class Solution {
+public:
+    int maximumProfit(vector<int>& present, vector<int>& future, int budget) 
+    {
+        int n = present.size();
+
+        vector<int>dp(1001);
+        for (int i=0; i<n; i++)
+            for (int j=budget; j>=present[i]; j--)
+            {
+                dp[j] = max(dp[j], dp[j-present[i]]+future[i]-present[i]);
+            }
+
+        return dp[budget];
+    }
+};

Dynamic_Programming/2291.Maximum-Profit-From-Trading-Stocks/Readme.md

@@ -0,0 +1,3 @@
+### 2291.Maximum-Profit-From-Trading-Stocks
+
+非常直观的01背包问题。挨个遍历物品。考察对于给定某budget情况下，加入这个物品是否能带来更大的收益，即```dp[budget] = max(dp[budget], dp[budget-cost[i]] + profit[i])```

Readme.md

@@ -680,6 +680,7 @@
 [1049.Last-Stone-Weight-II](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1049.Last-Stone-Weight-II) (H-)    
 [1449.Form-Largest-Integer-With-Digits-That-Add-up-to-Target](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1449.Form-Largest-Integer-With-Digits-That-Add-up-to-Target) (H-)  
 [1981.Minimize-the-Difference-Between-Target-and-Chosen-Elements](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1981.Minimize-the-Difference-Between-Target-and-Chosen-Elements) (M+)    
+[2291.Maximum-Profit-From-Trading-Stocks](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/2291.Maximum-Profit-From-Trading-Stocks) (M)     
 * ``键盘型``  
 [650.2-Keys-Keyboard](https://github.com/wisdompeak/LeetCode/blob/master/Dynamic_Programming/650.2-Keys-Keyboard) (M+)   
 [651.4-Keys-Keyboard](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/651.4-Keys-Keyboard) (M+)    
@@ -736,7 +737,6 @@
 * ``状态压缩DP``   
 [465.Optimal-Account-Balancing](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/465.Optimal-Account-Balancing) (H)  
 [691.Stickers-to-Spell-Word](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/691.Stickers-to-Spell-Word) (H)    
-[943.Find-the-Shortest-Superstring](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/943.Find-the-Shortest-Superstring) (H+)    
 [1125.Smallest-Sufficient-Team](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1125.Smallest-Sufficient-Team) (H)   
 [1349.Maximum-Students-Taking-Exam](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1349.Maximum-Students-Taking-Exam) (H)   
 [1411.Number-of-Ways-to-Paint-N×3-Grid](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1411.Number-of-Ways-to-Paint-N%C3%973-Grid) (M)    
@@ -754,11 +754,14 @@
     [1986.Minimum-Number-of-Work-Sessions-to-Finish-the-Tasks](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1986.Minimum-Number-of-Work-Sessions-to-Finish-the-Tasks) (M+)     
     [2152.Minimum-Number-of-Lines-to-Cover-Points](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/2152.Minimum-Number-of-Lines-to-Cover-Points) (H-)     
     * ``带权二分图``   
-[1066.Campus-Bikes-II](https://github.com/wisdompeak/LeetCode/tree/master/BFS/1066.Campus-Bikes-II) (H+)    
-[1595.Minimum-Cost-to-Connect-Two-Groups-of-Points](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1595.Minimum-Cost-to-Connect-Two-Groups-of-Points) (H)  
-[1879.Minimum-XOR-Sum-of-Two-Arrays](https://github.com/wisdompeak/LeetCode/tree/master/BFS/1879.Minimum-XOR-Sum-of-Two-Arrays) (H)  
-[1947.Maximum-Compatibility-Score-Sum](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1947.Maximum-Compatibility-Score-Sum) (H)  
-[2172.Maximum-AND-Sum-of-Array](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/2172.Maximum-AND-Sum-of-Array) (H)    
+   [1066.Campus-Bikes-II](https://github.com/wisdompeak/LeetCode/tree/master/BFS/1066.Campus-Bikes-II) (H+)    
+   [1595.Minimum-Cost-to-Connect-Two-Groups-of-Points](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1595.Minimum-Cost-to-Connect-Two-Groups-of-Points) (H)  
+   [1879.Minimum-XOR-Sum-of-Two-Arrays](https://github.com/wisdompeak/LeetCode/tree/master/BFS/1879.Minimum-XOR-Sum-of-Two-Arrays) (H)  
+   [1947.Maximum-Compatibility-Score-Sum](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1947.Maximum-Compatibility-Score-Sum) (H)  
+   [2172.Maximum-AND-Sum-of-Array](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/2172.Maximum-AND-Sum-of-Array) (H)    
+   * ``TSP``   
+   [943.Find-the-Shortest-Superstring](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/943.Find-the-Shortest-Superstring) (H+)    
+   [2247.Maximum-Cost-of-Trip-With-K-Highways](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/2247.Maximum-Cost-of-Trip-With-K-Highways) (H)    
 * ``Catalan``   
 [096.Unique-Binary-Search-Trees](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/096.Unique-Binary-Search-Trees) (M+)  
 [1259.Handshakes-That-Don't-Cross](https://github.com/wisdompeak/LeetCode/tree/master/Dynamic_Programming/1259.Handshakes-That-Don't-Cross) (M+)