پست#include <bits/stdc++.h>

#include <bits/stdc++.h> using namespace std; class LibrarySystem { private: unordered_map<int, int> bookBorrower; unordered_map<int, bool> bookStatus; unordered_map<int, unordered_set<int>> userBooks; unordered_map<int, int> userIssuedCount; map<pair<int,int>, int> userBookCount; unordered_map<int, int> bookFrequency; public: LibrarySystem(){} bool checkout(int library_card_id, int book_id) { if(userIssuedCount[library_card_id] >= 50) return false; if(userBooks[library_card_id].size() >= 5) return false; if(bookStatus.find(book_id)!=bookStatus.end() && bookStatus[book_id]==false) return false; if(userBookCount[{library_card_id, book_id}] >= 3) return false; bookStatus[book_id] = false; bookBorrower[book_id] = library_card_id; userBooks[library_card_id].insert(book_id); userIssuedCount[library_card_id]++; userBookCount[{library_card_id, book_id}]++; bookFrequency[book_id]++; return true; } bool returnBook(int library_card_id, int book_id){ if(bookBorrower.find(book_id)==bookBorrower.end()) return false; if(bookBorrower[book_id]!=library_card_id) return false; if(bookStatus[book_id]==true) return false; bookStatus[book_id] = true; bookBorrower.erase(book_id); userBooks[library_card_id].erase(book_id); return true; } bool available(int book_id){ if(bookStatus.find(book_id)==bookStatus.end()) return true; return bookStatus[book_id]; } int borrower(int book_id){ if(bookBorrower.find(book_id)==bookBorrower.end()) return -1; return bookBorrower[book_id]; } int count(int library_card_id){ return userIssuedCount[library_card_id]; } int frequency(int book_id){ return bookFrequency[book_id]; } }; Library system ✅ //SIEMENS