HJ8-合并表记录

#include<iostream>
using namespace std;
#include<map>





int main()
{
    map<int,int>m;
    int n;
    cin >> n;
    while(n--)
    {
        int a = 0, b = 0;
        cin >> a >> b;
        if(m.find(a)==m.end())
        {
            m.insert(make_pair(a,b));
        }
        else
        {
            m[a] += b;
        }
        
    }
    //sort(m.begin(),m.end());　　　　//
    //for_each(m.begin(),m.end(),myPrint);
    for(map<int,int>::iterator it =m.begin();it!=m.end();it++)
    {
        cout << it->first << " " << it->second << endl;
    }
    
    
}

 1 #include<iostream>
 2 using namespace std;
 3 #include<map>
 4 typedef pair<int, int> pr;
 5 #include<vector>
 6 #include<algorithm>
 7 
 8 class Greater
 9 {
10 public:
11     bool operator()(pr p1, pr p2)　　//这是sort中迭代器解引用的类型，要比较，所以传入两个pr类型（pair<int,int>）
12     {
13         return p1.second > p2.second;　　//比较的是对组的第二个（second），降序，所以规则是 左>右
14     }
15 };
16 
17 int main()
18 {
19     map<int, int>m;
20     m.insert(make_pair(1, 10));
21     m.insert(make_pair(2, 90));
22     m.insert(make_pair(3, 70));
23     m.insert(make_pair(4, 20));
24     m.insert(make_pair(5, 80));
25     m.insert(make_pair(6, 40));
26 
27     vector<pr> v;
28     pr p;
29     
30     for (map<int, int>::iterator it = m.begin(); it != m.end(); it++)
31     {
32         p.first = it->first;
33         p.second = it->second;
34         v.push_back(p);
35     }
36     cout << "vector原始内容打印" << endl;
37     for (vector<pr>::iterator it3 = v.begin(); it3 != v.end(); it3++)
38     {
39         cout << it3->first << " " << it3->second << endl;
40     }
41 
42 
43     sort(v.begin(), v.end(), Greater());　　//利用二元谓词作为sort的排序规则参数
44 
45     cout << "----------------" << endl;
46     cout << "vector按value排序后打印" << endl;
47     for (vector<pr>::iterator it2 = v.begin(); it2 != v.end(); it2++)
48     {
49         cout << it2->first << " " << it2->second << endl;
50     }
51 
52 
53 
54 
55     cout << "----------------" << endl;
56     cout << "原始的map" << endl;
57     for (map<int, int>::iterator it1 = m.begin(); it1 != m.end(); it1++)
58     {
59 
60         cout << it1->first << " " << it1->second << endl;
61     }
62 
63 
64 
65 
66 
67 
68     return 0;
69 }

 1 #include<iostream>
 2 using namespace std;
 3 #include<map>
 4 #include<algorithm>
 5 typedef pair<int,int> pr;
 6 #include<vector>
 7 
 8 
 9 class Greater
10 {
11 public:
12     bool operator()(pr p1,pr p2)
13     {
14         return p1.second > p2.second;
15     }
16     
17 };
18 
19 
20 int main()
21 {
22     map<int,int>m;
23     int n;
24     cin >> n;
25     while(n--)
26     {
27         int a = 0, b = 0;
28         cin >> a >> b;
29         if(m.find(a)==m.end())
30         {
31             m.insert(make_pair(a,b));
32         }
33         else
34         {
35             m[a] += b;
36         }
37         
38     }
39     //sort(m.begin(),m.end());
40     //for_each(m.begin(),m.end(),myPrint);
41     //放到pair里，放到vector里，vector排序，vector输出
42         /*
43     vector<pr> v;
44     pr p;
45     for(map<int,int>::iterator it=m.begin();it!=m.end();it++)
46     {
47         p.first  = it->first;
48         p.second = it->second;
49         v.push_back(p);
50     }
51     
52     sort(v.begin(),v.end(),Greater());
53     for(vector<pr>::iterator it =v.begin();it!=v.end();it++)
54     {
55         cout << it->first << " " << it->second << endl;
56     }
57         */
58     
59     
60 
61     
62     for(map<int,int>::iterator it =m.begin();it!=m.end();it++)
63     {
64         cout << it->first << " " << it->second << endl;
65     }
66 
67     
68 }