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March 30, 2024 21:54
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user_friendly_hash.cpp
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| #include <algorithm> | |
| #include <iostream> | |
| #include <string> | |
| #include <utility> | |
| #include <vector> | |
| using namespace std; | |
| unsigned long long shash(const string& s) { | |
| const unsigned long long P = 131; | |
| const unsigned long long M = 1000000007; | |
| const long long N = s.size(); | |
| unsigned long long h = 0; | |
| unsigned long long p = 1; | |
| for (size_t i = 0; i < s.size(); ++i) { | |
| const char c = s[N - i - 1]; | |
| h = (h + (c * p)) % M; | |
| p = (p * P) % M; | |
| } | |
| return h % M; | |
| } | |
| unsigned long long shash_minus_1(const string& s) { | |
| const unsigned long long P = 131; | |
| const unsigned long long M = 1000000007; | |
| const long long N = s.size(); | |
| unsigned long long h = 0; | |
| unsigned long long p = 1; | |
| for (size_t i = 0; i < s.size(); ++i) { | |
| const char c = s[N - i - 1]; | |
| h = (h + (c * p)) % M; | |
| p = (p * P) % M; | |
| } | |
| return h % M; | |
| } | |
| long long remainder(long long a, long long b) | |
| { | |
| return a - (a / b) * b; | |
| } | |
| vector<int> authEvents(vector<vector<string>> events) { | |
| vector<int> results; | |
| unsigned long long current_password_hash = 0; | |
| unsigned long long current_nice_hash = 0; | |
| for (auto& event : events) { | |
| auto& cmd = event[0]; | |
| if (cmd == "setPassword") { | |
| current_password_hash = shash(event[1]); | |
| current_nice_hash = remainder(shash(event[1] + "X") - 'X', 1000000007); | |
| // std::cout << "new hash: " << current_password_hash << "\n"; | |
| // std::cout << "new nice hash: " << current_nice_hash << "\n"; | |
| } else if (cmd == "authorize") { | |
| auto h = std::stoi(event[1]); | |
| std::cout << "authorize " << h << "\n"; | |
| if (h == current_password_hash) { | |
| results.push_back(1); | |
| } else { | |
| bool found = false; | |
| for (size_t i = 0; i <= 255; ++i) { | |
| if ((h - i) == current_nice_hash) { | |
| found = true; | |
| break; | |
| } | |
| } | |
| if (found) { | |
| results.push_back(1); | |
| } else { | |
| results.push_back(0); | |
| } | |
| } | |
| } | |
| } | |
| return results; | |
| } | |
| int main() { | |
| vector<vector<string>> events = { | |
| {"setPassword", "cAr1"}, | |
| {"authorize", "223691457"}, | |
| {"authorize", "303580761"}, | |
| {"authorize", "100"}, | |
| {"setPassword", "d"}, | |
| {"authorize", "100"}, | |
| {"authorize", "101"}, | |
| }; | |
| for (auto a : authEvents(events)) { | |
| cout << a << "\n"; | |
| } | |
| } |
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