#include <iostream> #include <vector> #include <string>  using namespace std;  int main() {     int n;     cin >> n;      vector<string> history;  // 用于存储浏览历史     int currentIndex = -1;   // 当前所在页面的索引      for (int i = 0; i < n; i++) {         string operation;         cin >> operation;          if (operation == "VISIT") {             string url;             cin >> url;              // 清除当前索引之后的所有历史记录             if (currentIndex < history.size() - 1) {                 history.erase(history.begin() + currentIndex + 1, history.end());             }             // 添加新的网址到历史记录中             history.push\_back(url);             currentIndex++;             cout << url << endl;         } else if (operation == "BACK") {             if (currentIndex > 0) {                 currentIndex--;                 cout << history[currentIndex] << endl;             } else {                 cout << "Ignore" << endl;             }         } else if (operation == "FORWARD") {             if (currentIndex < history.size() - 1) {                 currentIndex++;                 cout << history[currentIndex] << endl;             } else {                 cout << "Ignore" << endl;             }         }     }      return 0; }