1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
/*************************************************************************
    > File Name: Lfu.cpp
    > Author:zhangtx
    > Mail: zhangtx@jinher.com 
    > Created Time: 2018年03月30日 星期五 15时50分24秒
 ************************************************************************/
#include <map>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
using namespace std;
class LFUCache {
public:
    /*
    * @param capacity: An integer
    */LFUCache(int capacity) {
        // do intialization if necessary
        m_capacity=capacity;
        m_count = 0;
    }

    void remove_least_used_key()
    {
        map<int,int>::iterator iterBegin=m_countMap.begin();
        map<int,int>::iterator pos      =iterBegin;
        for(;iterBegin!=m_countMap.end();iterBegin++)
        {
            if (pos->second>iterBegin->second)
            {
		pos=iterBegin;
            }
	    else if (pos->second==iterBegin->second)
	    {
		if (m_keytotime[pos->first]>m_keytotime[iterBegin->first])
	        {
		     pos=iterBegin;
		}
	    }
        }
	cout<<endl<<"remove "<<pos->first<<endl;
        m_dataMap.erase(m_dataMap.find(pos->first));
	m_keytotime.erase(m_keytotime.find(pos->first));
        m_countMap.erase(pos);
        m_count--;
        
    }

    /*
     * @param key: An integer
     * @param value: An integer
     * @return: nothing
     */
    void set(int key, int value) {
        // write your code here
        if (m_countMap.find(key) != m_countMap.end())
        {
            m_countMap[key]=m_countMap[key]+1;
	    m_dataMap[key]=value;
        }
        else
        {
            if ((m_count>=m_capacity))
            {
                remove_least_used_key();
            }
            m_countMap[key]=1;
            m_dataMap[key]=value;
            m_count++;
        }
	struct timezone tz;
	struct timeval tv;
	gettimeofday (&tv , &tz);
	m_keytotime[key]=tv.tv_sec*1000000+tv.tv_usec;
    }

    /*
     * @param key: An integer
     * @return: An integer
     */
    int get(int key) {
        // write your code here
        if (m_dataMap.find(key)!=m_dataMap.end())
        {		

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
             struct timezone tz;
	     struct timeval tv;
	     gettimeofday (&tv , &tz);
	     m_keytotime[key]=tv.tv_sec*1000000+tv.tv_usec;
			
	     m_countMap[key]=m_countMap[key]+1;
             return m_dataMap[key];
        }
        else
            return -1;
    }
private:
    int m_capacity;
    int m_count;
    map<int,int> m_dataMap;
    map<int,int> m_countMap;
    map<int,long> m_keytotime;
    
};
int main(int argc,char *argv[])
{
	cout<<endl;
	cout<<endl;
	LFUCache *lfu=new LFUCache(3);
	lfu->set(1,10);
	lfu->set(2,20);
	lfu->set(3,30);
	cout<<lfu->get(1)<<" ";
	lfu->set(4, 40);
	cout<<lfu->get(4)<<" ";
	cout<<lfu->get(3)<<" ";
	cout<<lfu->get(2)<<" ";
	cout<<lfu->get(1)<<" ";
        lfu->set(5, 50);
	cout<<lfu->get(1)<<" ";
	cout<<lfu->get(2)<<" ";
	cout<<lfu->get(3)<<" ";
	cout<<lfu->get(4)<<" ";
	cout<<lfu->get(5)<<" ";
	delete lfu;

	cout<<endl;
	cout<<endl;
	cout<<endl;
}