新增了ActionManager类，用于管理撤回、重做

mystl/my_vector.h

@@ -211,6 +211,24 @@ public:
         long long operator-(iterator other) const {
             return ptr - other.ptr;
         }
+
+        iterator& operator+=(size_t n) {
+            ptr += n;
+            return *this;
+        }
+        iterator& operator-=(size_t n) {
+            ptr -= n;
+            return *this;
+        }
+        
+        friend iterator operator++(iterator& ite) {
+            ++ite.ptr;
+            return ite;
+        }
+        friend iterator operator--(iterator& ite) {
+            --ite.ptr;
+            return ite;
+        }
     };
 
     iterator begin() {
@@ -224,6 +242,14 @@ public:
     void erase(iterator target) {
         erase(target - begin());
     }
+
+    void reverse() {
+        MyVector<T> tmp = *this;
+        for (size_t i = 0; i < m_size / 2; ++i) {
+            std::swap(tmp[i], tmp[m_size - i - 1]);
+        }
+        *this = tmp;
+    }
 };
 
 #endif // MY_VECTOR_H

utils/ActionManager.h

@@ -1,14 +1,148 @@
 #ifndef ACTIONMANAGER_H
 #define ACTIONMANAGER_H
 
-enum class EditAction {
+#include "../mystl/my_stack.h"
+#include <string>
+
+enum class EditActiontype {
     Initialize,
     Insert,
     Delete,
 };
 
-class ActionManager {
+struct EditAction {
+    EditActiontype type;
+    int pos;
+    std::string content;
+};
 
-}
+class ActionManager {
+private:
+    MyStack<MyVector<EditAction>> undoStack_, redoStack_;
+    std::string content_;
+
+    MyVector<EditAction> calculateEditActions(const std::string &str1, const std::string &str2) { // 规定Editor只会在删除或者插入时提交，因此只会同时存在一种操作
+        int m = str1.length();
+        int n = str2.length();
+        MyVector<MyVector<int>> dp(m + 1, MyVector<int>(n + 1));
+
+        for (int i = 0; i <= m; ++i) {
+            dp[i][0] = i;
+        }
+        for (int j = 0; j <= n; ++j) {
+            dp[0][j] = j;
+        }
+
+        for (int i = 1; i <= m; ++i) {
+            for (int j = 1; j <= n; ++j) {
+                if (str1[i - 1] == str2[j - 1]) {
+                    dp[i][j] = dp[i - 1][j - 1];
+                } else {
+                    dp[i][j] = std::min(dp[i - 1][j], dp[i][j - 1]) + 1;
+                }
+            }
+        }
+
+        // 回溯以找到编辑操作
+        MyVector<EditAction> actions;
+        int i = m, j = n;
+        while (i > 0 && j > 0) {
+            if (str1[i - 1] == str2[j - 1]) {
+                --i;
+                --j;
+            } else if (dp[i][j] == dp[i - 1][j] + 1) {
+                actions.push_back({EditActiontype::Delete, i - 1, std::string(1, str1[i - 1])});
+                --i;
+            } else if (dp[i][j] == dp[i][j - 1] + 1) {
+                actions.push_back({EditActiontype::Insert, i, std::string(1, str2[j - 1])});
+                --j;
+            }
+        }
+
+        while (i > 0) {
+            actions.push_back({EditActiontype::Delete, i - 1, std::string(1, str1[i - 1])});
+            --i;
+        }
+
+        while (j > 0) {
+            actions.push_back({EditActiontype::Insert, i, std::string(1, str2[j - 1])});
+            --j;
+        }
+
+        actions.reverse();
+
+        // 考虑到先前进行的插入和删除操作，对随后插入和删除的位置进行修正
+        int offset = 0;
+        for (int i = 0; i < actions.size(); ++i) {
+            if (actions[i].type == EditActiontype::Insert) {
+                actions[i].pos += offset;
+                offset++;
+            } else if (actions[i].type == EditActiontype::Delete) {
+                actions[i].pos += offset;
+                offset--;
+            }
+        }
+
+        return actions;
+    }
+
+    std::string applyEditAction(MyVector<EditAction> &actions, std::string &content) {
+        std::string newContent = content;
+        for(int i = 0; i < actions.size(); i++) {
+            if(actions[i].type == EditActiontype::Insert) {
+                newContent.insert(actions[i].pos, actions[i].content);
+            } else if(actions[i].type == EditActiontype::Delete) {
+                newContent.erase(actions[i].pos, actions[i].content.size());
+            }
+        }
+        return newContent;
+    }
+
+public:
+    ActionManager() {
+    }
+    ActionManager(const std::string &content) {
+        content_ = content;
+    }
+
+    void updateContent(const std::string &content) {
+        redoStack_.clear();
+        MyVector<EditAction> actions = calculateEditActions(content_, content);
+        content_ = content;
+        undoStack_.push(actions);
+    }
+
+    void undo() {
+        if (undoStack_.empty()) {
+            return;
+        }
+        MyVector<EditAction> actions = undoStack_.top();
+        undoStack_.pop();
+        std::string newContent = applyEditAction(actions, content_);
+        redoStack_.push(calculateEditActions(content_, newContent));
+        content_ = newContent;
+    }
+
+    void redo() {
+        if (redoStack_.empty()) {
+            return;
+        }
+        MyVector<EditAction> actions = redoStack_.top();
+        redoStack_.pop();
+        std::string newContent = applyEditAction(actions, content_);
+        undoStack_.push(calculateEditActions(content_, newContent));
+        content_ = newContent;
+    }
+
+    void setContent(const std::string &content) {
+        content_ = content;
+        undoStack_.clear();
+        redoStack_.clear();
+    }
+
+    std::string getContent() {
+        return content_;
+    }
+};
 
 #endif

utils/ActionManager_test.cpp

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include "ActionManager.h"
+#include "../mystl/my_vector.h"
+
+using namespace std;
+
+int main() {
+    ActionManager am;
+    MyVector<EditAction> v;
+    v = am.calculateEditActions("i can see you, but u dont love me", "i cant hug u, but i love you");
+    printf("Actions: %zu\n", v.size());
+    //replay test
+    std::string s1 = "i can see you, but u dont love me";
+    for(int i = 0; i < v.size(); i++) {
+        if(v[i].type == EditActiontype::Insert) {
+            s1.insert(v[i].pos, v[i].content);
+        } else if(v[i].type == EditActiontype::Delete) {
+            s1.erase(v[i].pos, v[i].content.size());
+        }
+    }
+    printf("%s\n", s1.c_str());
+    return 0;
+}