#include <iostream> #include <vector> #include <string> #include <sstream> #include <cstdlib> using namespace std; struct TypeNode { string type_name; TypeNode* first = NULL; TypeNode* second = NULL; TypeNode(string t) : type_name(t), first(NULL), second(NULL) {} }; vector<TypeNode*> vars; vector<string> var_names; void addVariable(const string& name, const string& type_str) { if (type_str == "int" || type_str == "double") { vars.push_back(new TypeNode(type_str)); } else { size_t pos = type_str.find("<"); string base_type = type_str.substr(0, pos); if (base_type != "pair") { cerr << "Error: Invalid type definition!" << endl; exit(-1); } string inner_types = type_str.substr(pos + 1, type_str.size() - pos - 2); stringstream ss(inner_types); string left_type, right_type; getline(ss, left_type, ','); getline(ss, right_type); TypeNode* node = new TypeNode("pair"); node->first = new TypeNode(left_type); node->second = new TypeNode(right_type); vars.push_back(node); } var_names.push_back(name); } TypeNode* getTypeNodeByName(const string& name) { for (size_t i = 0; i < var_names.size(); ++i) { if (var_names[i] == name) return vars[i]; } return NULL; } string queryType(TypeNode* root, const vector<string>& steps) { if (!root) return ""; if (steps.empty()) return root->type_name; string step = steps.front(); if (step == "first" && root->first) { return queryType(root->first, vector<string>(steps.begin() + 1, steps.end())); } else if (step == "second" && root->second) { return queryType(root->second, vector<string>(steps.begin() + 1, steps.end())); } else { return ""; } } string resolveQuery(const string& query_str) { size_t dot_pos = query_str.find('.'); string var_name = query_str.substr(0, dot_pos); string rest = query_str.substr(dot_pos + 1); TypeNode* root = getTypeNodeByName(var_name); if (!root) return ""; vector<string> steps; while (!rest.empty()) { size_t next_dot = rest.find('.'); string current_step = rest.substr(0, next_dot); steps.push_back(current_step); if (next_dot == string::npos) break; rest = rest.substr(next_dot + 1); } return queryType(root, steps); } int main() { int n, q; cin >> n >> q; cin.ignore(); for (int i = 0; i < n; ++i) { string line; getline(cin, line); size_t space_pos = line.find(' '); string type_def = line.substr(0, space_pos); string var_name = line.substr(space_pos + 1); if (!var_name.empty() && var_name[var_name.size()-1] == ';') { var_name.erase(var_name.size()-1); } addVariable(var_name, type_def); } for (int i = 0; i < q; ++i) { string query; cin >> query; cout << resolveQuery(query) << endl; } return 0; }样例输入 #1 5 5 int a1; double a2; pair<int,int> pr; pair<pair<int,int>,pair<int,int>> BBKKBKK; pair<int,pair<pair<double,int>,double>> __frost_ice; a1 a2 pr.first BBKKBKK __frost_ice.second.first.second 错误输出： int 期望输出： int double int pair<pair<int,int>,pair<int,int>> int