题目链接如下：

Online Judge

我的代码如下：

#include <string>
#include <iostream>
#include <map>
#include <set>
// #define debugint T, loc1, loc2;
std::string s, key, value;
char ch[] = "+-*";int main(){#ifdef debugfreopen("0.txt", "r", stdin);freopen("1.txt", "w", stdout);#endifscanf("%d\n", &T);while (T--){std::map<std::string, std::string> mp[2];std::set<std::string> keys[3];for (int i = 0; i < 2; ++i){getline(std::cin, s);s = s.substr(1);s.back() = ',';while (s.find(":") != std::string::npos){loc1 = s.find(":");key = s.substr(0, loc1);loc2 = s.find(",");value = s.substr(loc1 + 1, loc2 - loc1 - 1);s = s.substr(loc2 + 1);mp[i][key] = value;}}for (auto it = mp[0].begin(); it != mp[0].end(); ++it){if (!mp[1].count(it->first)){keys[1].insert(it->first);} else if (it->second != mp[1][it->first]){keys[2].insert(it->first);}}for (auto it = mp[1].begin(); it != mp[1].end(); ++it){if (!mp[0].count(it->first)){keys[0].insert(it->first);}}for (int i = 0; i < 3; ++i){if (!keys[i].empty()){for (auto it = keys[i].begin(); it != keys[i].end(); ++it){printf("%c%s", it == keys[i].begin() ? ch[i] : ',', (*it).c_str());}printf("\n");}}if (keys[0].empty() && keys[1].empty() && keys[2].empty()){printf("No changes\n");}printf("\n");}#ifdef debugfclose(stdin);fclose(stdout);#endifreturn 0;
}

看到网上说双指针做，于是又改了一下：

#include <string>
#include <iostream>
#include <map>
#include <set>
// #define debugint T, loc1, loc2;
std::string s, key, value;
char ch[] = "+-*";int main(){#ifdef debugfreopen("0.txt", "r", stdin);freopen("1.txt", "w", stdout);#endifscanf("%d\n", &T);while (T--){std::map<std::string, std::string> mp[2];std::set<std::string> keys[3];for (int i = 0; i < 2; ++i){getline(std::cin, s);s = s.substr(1);s.back() = ',';while (s.find(":") != std::string::npos){loc1 = s.find(":");key = s.substr(0, loc1);loc2 = s.find(",");value = s.substr(loc1 + 1, loc2 - loc1 - 1);s = s.substr(loc2 + 1);mp[i][key] = value;}}auto it1 = mp[0].begin();auto it2 = mp[1].begin();while (it1 != mp[0].end() && it2 != mp[1].end()){if (it1->first < it2->first){keys[1].insert(it1->first);++it1;} else if (it1->first > it2->first){keys[0].insert(it2->first);++it2;} else {if (it1->second != it2->second){keys[2].insert(it1->first);}++it1;++it2;}}for (; it1 != mp[0].end(); ++it1){keys[1].insert(it1->first);}for (; it2 != mp[1].end(); ++it2){keys[0].insert(it2->first);}for (int i = 0; i < 3; ++i){if (!keys[i].empty()){for (auto it = keys[i].begin(); it != keys[i].end(); ++it){printf("%c%s", it == keys[i].begin() ? ch[i] : ',', (*it).c_str());}printf("\n");}}if (keys[0].empty() && keys[1].empty() && keys[2].empty()){printf("No changes\n");}printf("\n");}#ifdef debugfclose(stdin);fclose(stdout);#endifreturn 0;
}