unordered_map四种插入效率的对比

唐康林

unordered_map四种插入效率的对比

1.     clock_t start = clock();
   
2.     int numbers = 1000000;
   
3.     std::unordered_map<int, string> a1;
   
4.     for (int i = 0; i < numbers; ++i)
   
5.     {
   
6.         a1.insert(pair<int, string>(i, "tkl"));
   
7.     }
   
8.     clock_t finish = clock();
   
9.     ECHO("a1: %f\n", (double)(finish - start) / CLOCKS_PER_SEC);
   
10.     start = clock();
    
11.     std::unordered_map<int, string> a2;
    
12.     for (int i = 0; i < numbers; ++i)
    
13.     {
    
14.         a2.insert(make_pair(i, "tkl"));
    
15.     }
    
16.     finish = clock();
    
17.     ECHO("a2: %f\n", (double)(finish - start) / CLOCKS_PER_SEC);
    
18.     start = clock();
    
19.     std::unordered_map<int, string> a3;
    
20.     for (int i = 0; i < numbers; ++i)
    
21.     {
    
22.         a3.insert(std::unordered_map<int, string>::value_type(i, "tkl"));
    
23.     }
    
24.     finish = clock();
    
25.     ECHO("a3: %f\n", (double)(finish - start) / CLOCKS_PER_SEC);
    
26.     start = clock();
    
27.     std::unordered_map<int, string> a4;
    
28.     for (int i = 0; i < numbers; ++i)
    
29.     {
    
30.         a4[i] = "tkl";
    
31.     }
    
32.     finish = clock();
    
33.     ECHO("a4: %f\n", (double)(finish - start) / CLOCKS_PER_SEC);

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