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给一个数，找出满足大于这个数，并且相邻每一位不相同的最小数，比如1121的解是1201，99的解是101
#include <iostream> #include <string> std::string solve(int x) { std::string s = std::to_string(x + 1); int n = s.length(); for (int i = 0; i < n; ++i) { for (char c = ' '; i < n && c != s[i]; ++i) { c = s[i]; } if (i == n) break; std::string str = s.substr(0, i + 1); int t = std::stoi(str) + 1; n = str.length(); s.replace(s.begin(), s.begin() + i + 1, std::to_string(t)); } bool zero = s[n-1] - '0'; for (int i = n; i < s.length(); ++i, zero = !zero) { s[i] = zero ? '0' : '1'; } return s; } int main() { int x; while (std::cin >> x) { std::cout << solve(x) << "\n"; } return 0; } // 字符串版 #include <iostream> #include <string> #include <cassert> std::string add(std::string s) { int n = s.length(); assert(s.length() != 0); if (s[0] == '-') { if (s == "-1") return "0"; for (int i = n - 1; i >= 1; --i) { if (s[i] != '0') { s[i]--; break; } s[i] = '9'; } int k = 1; while (s[k] == '0') k++; return "-" + s.substr(k); } for (int i = n - 1; i >= 0; --i) { if (s[i] != '9') { s[i]++; return s; } s[i] = '0'; } return "1" + s; } std::string solve(std::string x) { std::string s = add(x); int n = s.length(); for (int i = 0; i < n; ++i) { for (char c = ' '; i < n && c != s[i]; ++i) { c = s[i]; } if (i == n) break; std::string str = s.substr(0, i + 1); std::string t = add(str); n = str.length(); s.replace(s.begin(), s.begin() + i + 1, t); } bool zero = s[n-1] - '0'; for (int i = n; i < s.length(); ++i, zero = !zero) { s[i] = zero ? '0' : '1'; } return s; } int main() { std::string x; while (std::cin >> x) { std::cout << solve(x) << "\n"; } return 0; } 系统设计题，设计一个1000个玩家的游戏排行榜，要求满足高并发
// 感觉在分块加锁，和效率之间应该还有不少的提升空间 #include <iostream> #include <map> #include <shared_mutex> #include <vector> #include <future> #include <thread> #include <chrono> #include <random> class Shard { public: void addOrUpdatePlayer(int playerId, int score) { std::unique_lock<std::shared_mutex> lock(mtx); auto it = playerToScore.find(playerId); if (it != playerToScore.end()) { scoreToPlayer.erase(scoreToPlayer.find(it->second)); } playerToScore[playerId] = score; scoreToPlayer.insert({score, playerId}); } std::vector<std::pair<int, int>> getToPlayer(int topN) { std::shared_lock<std::shared_mutex> lock(mtx); std::vector<std::pair<int, int>> topPlayer; auto it = scoreToPlayer.rbegin(); while (it != scoreToPlayer.rend() && topN > 0) { topPlayer.emplace_back(it->second, it->first); ++it; --topN; } return topPlayer; } private: std::map<int, int> playerToScore; std::multimap<int, int> scoreToPlayer; std::shared_mutex mtx; }; class GameRanking { public: GameRanking(int shardCount): shardCount(shardCount), shards(shardCount){ } void addOrUpdatePlayer(int playerId, int score) { int shardIndex = getShardIndex(playerId); std::async(std::launch::async, [this, shardIndex, playerId, score](){ shards[shardIndex].addOrUpdatePlayer(playerId, score); }).get(); } std::vector<std::pair<int, int>> getTopPlayers(int topN) { std::vector<std::future<std::vector<std::pair<int, int>>>> futures; for (int i = 0; i < shardCount; ++i) { futures.push_back(std::async(std::launch::async, [this, i, topN] { return shards[i].getToPlayer(topN); })); } std::vector<std::pair<int, int>> allTopPlayer; for (auto & future : futures) { auto shardTopPlayers = future.get(); allTopPlayer.insert(allTopPlayer.end(), shardTopPlayers.begin(), shardTopPlayers.end()); } std::sort(allTopPlayer.begin(), allTopPlayer.end(), [] (const auto& a, const auto& b) { return b.second < a.second; }); if (allTopPlayer.size() > topN) { allTopPlayer.resize(topN); } return allTopPlayer; } private: int shardCount; std::vector<Shard> shards; int getShardIndex(int playerId) { return playerId % shardCount; } }; int main() { const int shardcount = 10; const int playercount = 1000; GameRanking ranking(shardcount); std::random_device rd; std::mt19937 gen(rd()); std::uniform_int_distribution<> dis(1, 10000); auto start = std::chrono::high_resolution_clock::now(); for (int i = 1; i <= playercount; ++i) { int score = dis(gen); ranking.addOrUpdatePlayer(i, score); } auto end = std::chrono::high_resolution_clock::now(); std::chrono::duration<double> elapsed = end - start; std::cout << "time taken to add 1000 players: " << elapsed.count() << " seconds\n"; start = std::chrono::high_resolution_clock::now(); auto topplayers = ranking.getTopPlayers(10); end = std::chrono::high_resolution_clock::now(); elapsed = end - start; std::cout << "time taken to get top 10 players: " << elapsed.count() << " seconds\n"; for (const auto& player : topplayers) { std::cout << "player id: " << player.first << ", score: " << player.second << std::endl; } return 0; } 最后给大家推荐一个LinuxC/C++高级架构系统教程的学习资源与课程，可以帮助你有方向、更细致地学习C/C++后端开发，具体内容请见 https://xxetb.xetslk.com/s/1o04uB
