initial commit

2Q_cache.cpp

@@ -0,0 +1,85 @@
+
+#include <unordered_map>
+#include <list>
+#include "2Q_cache.h"
+
+class TwoCache {
+private:
+    //2 LRU caches
+
+    size_t cpct_q1;
+    std::unordered_map<int, std::list<int>::iterator> umap1;
+    std::list <int> q1;                                                 //fast queue - the most popular pages
+
+    size_t cpct_q2;
+    std::unordered_map<int, std::list<int>::iterator> umap2;
+    std::list <int> q2;                                                 //slow queue - if page asked at the first time put it to q2, if itasked from q2 it put it to q1,
+
+public:
+    TwoCache(size_t q1sz, size_t q2sz): cpct_q1(q1sz), cpct_q2(q2sz) {}    //ctor
+
+    int get_page(int id) {                                              //get_page(<int id>) - returns <int id> if page is found, and -1 if not 
+        if(umap1.find(id) != umap1.end()) {
+            q1.splice(q1.begin(), q1, umap1[id]);                       //if page did not find in the end of fast(q1) queue - put it in the begin
+
+            return id;
+        }
+
+        if (umap2.find(id) != umap2.end()) {                            //if page was not found in the end of slow queue - put is from slow(q2) to begin fast(q1)
+            auto it = umap2[id];
+
+            q2.splice(q2.begin(), q2, it);                              //put this page from queue to the slow
+            umap2.erase(id);                                            //delete it from slow queue
+
+            if (q1.size() == cpct_q1) {                                 //if q1 is overflowed delete oldest element from fast(q1)
+                umap1.erase(q1.back());
+                q1.pop_back();
+            }
+            q1.push_front(id);                                          //if it is not overflowed put it at the begin
+            umap2[id] = q1.begin();
+
+            return id;
+        } else return -1;                                               //page was not found - return PAGE_DID_NOT_FOUND = -1
+    }
+
+    void put_page(int id) {                                             //puts page in cache
+        if (umap1.find(id) != umap1.end()) {                            //if page is q1
+            return;
+        }
+
+        if (umap2.find(id) != umap2.end()) {                            //I know that in this case there will be 2 loops in get_page() i will think about it...
+            get_page(id);
+            return;
+        }
+
+        if (q1.size() == cpct_q1) {                                     //if overflow                    
+            umap1.erase(q1.back());
+            q1.pop_back();
+        }
+
+        if (q2.size() == cpct_q2) {
+            umap2.erase(q2.back());
+            q2.pop_back();
+        }
+
+        q1.push_front(id);                                              //in the end push page in cache
+        umap1[id] = q1.begin();
+    }
+
+
+
+
+
+    void info() {
+        std::cout << "q1 (the most usable): ";
+        for (auto i = q1.begin(); i != q1.end(); i++) {
+            std::cout << *i << " ";
+        }
+        std::cout << "\nq2(Less usable): ";
+        for (auto i = q2.begin(); i != q2.end(); i++) {
+            std::cout << *i << " ";
+        }
+        std::cout << "\ncapacity q1: " << cpct_q1 
+        << "\ncapacity q2: " << cpct_q2 << std::endl;
+    }
+};

2Q_cache.h

@@ -0,0 +1,14 @@
+#ifndef _2Q_CACHE_H_
+#define _2Q_CACHE_H_
+#include <iostream>
+#include <unordered_map>
+#include <list>
+
+class TwoCache {                                             
+public:
+    TwoCache(size_t q1sz, size_t q2sz); 
+    int get_page(int id);                                      
+    void put_page(int id);                                            
+    void info();
+};
+#endif

main.cpp

@@ -0,0 +1,23 @@
+#include <iostream>
+
+#include "2Q_cache.h"
+
+
+int main() {
+    TwoCache cache(2, 4);
+    cache.put_page(1);
+    cache.put_page(2);
+    std::cout << cache.get_page(1) << std::endl; // Вывод: 1
+    cache.put_page(1);
+    cache.put_page(2);
+    cache.put_page(1);
+    cache.put_page(2);
+    cache.put_page(1);
+    cache.put_page(2);
+    cache.put_page(3);
+    std::cout << cache.get_page(2) << std::endl; // Вывод: 2
+    cache.put_page(4); // Теперь 4 будет в Q1
+    std::cout << cache.get_page(3) << std::endl; // Вывод: -1 (3 нет в кэше)
+
+    return 0;
+}

makefile

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+
+TARGET = Q2
+
+CXX = g++
+
+CXXFLAGS = -Wall -Wextra -std=c++11
+
+SRCS = 2Q_cache.cpp main.cpp 
+
+OBJS = $(SRCS:.cpp=.o)
+
+all: $(TARGET)
+
+$(TARGET): $(OBJS)
+	$(CXX) -o $@ $^
+
+%.o: %.cpp
+	$(CXX) $(CXXFLAGS) -c $< -o $@
+
+clean:
+	rm -f $(OBJS) $(TARGET)
+
+run: $(TARGET)
+	./$(TARGET)
+
+.PHONY: all clean run