MAP,HASH_MAP和数组时间对比

  1 // ConsoleApplication5.cpp : 定义控制台应用程序的入口点。
  2 //
  3
  4 #include "stdafx.h"
  5
  6 #include <iostream>
  7 #include <hash_map>
  8 #include <map>
  9 #include <ctime>
 10
 11 using namespace std;
 12
 13 void testMap()
 14 {
 15     map<int, int> m;
 16     clock_t t1 = clock();
 17
 18     for (int i = 0; i < 1000; i++)
 19     {
 20         for (int j = 0; j < 1000; j++)
 21         {
 22             int tmp = (i << 16) + j;
 23             m[tmp] = 1;
 24         }
 25     }
 26     clock_t t2 = clock();
 27
 28     cout << "MAP: Add item time is " << ((double)(t2 - t1) / CLOCKS_PER_SEC) << "S" << endl;
 29
 30     clock_t t3 = clock();
 31     int sum = 0;
 32     for (int i = 0; i < 1000; i++)
 33     {
 34         for (int j = 0; j < 1000; j++)
 35         {
 36             int tmp = (i << 16) + j;
 37             sum += m[tmp];
 38         }
 39     }
 40
 41     clock_t t4 = clock();
 42
 43     cout << "MAP: look for item time is " << ((double)(t4 - t3) / CLOCKS_PER_SEC) << "S" << sum << endl;
 44
 45     int count = 0;
 46     clock_t t5 = clock();
 47     for (int i = 0; i < 1000; i++)
 48     {
 49         for (int j = 0; j < 1000; j++)
 50         {
 51             int tmp = (i << 16) + j;
 52             if (m[tmp] > 0)
 53             {
 54                 count++;
 55             }
 56         }
 57     }
 58
 59     clock_t t6 = clock();
 60     cout << "MAP: Calc Item time is " << ((double)(t6 - t5) / CLOCKS_PER_SEC) << "S,Count = " << count << endl;
 61 }
 62
 63 void testHashMap()
 64 {
 65     hash_map<int, int> m;
 66     clock_t t1 = clock();
 67
 68     for (int i = 0; i < 1000; i++)
 69     {
 70         for (int j = 0; j < 1000; j++)
 71         {
 72             int tmp = (i << 16) + j;
 73             m[tmp] = 1;
 74         }
 75     }
 76     clock_t t2 = clock();
 77
 78     cout << "HASH_MAP:time is " << ((double)(t2 - t1) / CLOCKS_PER_SEC) << "S" << endl;
 79
 80     clock_t t3 = clock();
 81     int sum = 0;
 82     for (int i = 0; i < 1000; i++)
 83     {
 84         for (int j = 0; j < 1000; j++)
 85         {
 86             int tmp = (i << 16) + j;
 87             sum += m[tmp];
 88         }
 89     }
 90
 91     clock_t t4 = clock();
 92
 93     cout << "HASH_MAP:time is " << ((double)(t4 - t3) / CLOCKS_PER_SEC) << "S, sum = " << sum << endl;
 94
 95     int count = 0;
 96     clock_t t5 = clock();
 97     for (int i = 0; i < 1000; i++)
 98     {
 99         for (int j = 0; j < 1000; j++)
100         {
101             int tmp = (i << 16) + j;
102             if (m[tmp] > 0)
103             {
104                 count++;
105             }
106         }
107     }
108
109     clock_t t6 = clock();
110     cout << "HASH_MAP: Calc Item time is " << ((double)(t6 - t5) / CLOCKS_PER_SEC) << "S,Count = " << count << endl;
111 }
112
113 void tesArray()
114 {
115     clock_t t1 = clock();
116
117     int *m = new int[1024 * 1024];
118     memset(m, 0, sizeof(*m));
119
120     for (int i = 0; i < 1000; i++)
121     {
122         for (int j = 0; j < 1000; j++)
123         {
124             int tmp = (i << 10) + j;
125             m[tmp] = 1;
126         }
127     }
128     clock_t t2 = clock();
129
130     cout << "ARRAY:time is " << ((double)(t2 - t1) / CLOCKS_PER_SEC) << "S" << endl;
131
132     clock_t t3 = clock();
133     int sum = 0;
134     for (int i = 0; i < 1000; i++)
135     {
136         for (int j = 0; j < 1000; j++)
137         {
138             int tmp = (i << 10) + j;
139             sum += m[tmp];
140         }
141     }
142
143     clock_t t4 = clock();
144
145     cout << "ARRAY:time is " << ((double)(t4 - t3) / CLOCKS_PER_SEC) << "S" << sum << endl;
146
147     int count = 0;
148     clock_t t5 = clock();
149     for (int i = 0; i < 1000; i++)
150     {
151         for (int j = 0; j < 1000; j++)
152         {
153             int tmp = (i << 10) + j;
154             if (m[tmp] > 0)
155             {
156                 count++;
157             }
158         }
159     }
160
161     clock_t t6 = clock();
162     cout << "ARRAY: Calc Item time is " << ((double)(t6 - t5) / CLOCKS_PER_SEC) << "S,Count = " << count << endl;
163
164     delete[] m;
165 }
166
167 int _tmain(int argc, _TCHAR* argv[])
168 {
169     testMap();
170     testHashMap();
171     tesArray();
172     return 0;
173 }

VS2013 + WIN7 64运行结果：

MAP: Add item time is 0.265S
MAP: look for item time is 0.094S1000000
MAP: Calc Item time is 0.094S,Count = 1000000
HASH_MAP:time is 0.203S
HASH_MAP:time is 0.047S, sum = 1000000
HASH_MAP: Calc Item time is 0.047S,Count = 1000000
ARRAY:time is 0S
ARRAY:time is 0S1000000
ARRAY: Calc Item time is 0S,Count = 1000000