多花费一些内存来提高性能

有时候时间效率和空间效率可能对立，此时应当分析那个更重要，作出适当的折衷。
例如多花费一些内存来提高性能。
 1 #include <iostream>
 2 #include <list>
 3 
 4 using namespace std;
 5 typedef list<int> INTLIST;
 6 
 7 //从前向后显示list队列的全部元素
 8 void put_list(INTLIST list, char *name)
 9 {
10     INTLIST::iterator plist;
11 
12     cout << "The contents of " << name << " : ";
13     for(plist = list.begin(); plist != list.end(); plist++)
14         cout << *plist << " ";
15     cout<<endl;
16 }
17 
18 //测试list容器的功能
19 /* run this program using the console pauser or add your own getch, system("pause") or input loop */
20 
21 int main(int argc, char** argv) {
22         //list1对象初始为空
23     INTLIST list1;   
24     //list2对象最初有10个值为6的元素  
25     INTLIST list2(10,6);  
26     //list3对象最初有3个值为6的元素  
27     INTLIST list3(list2.begin(),--list2.end());  
28 
29     //声明一个名为i的双向迭代器
30     INTLIST::iterator i;
31 
32     //从前向后显示各list对象的元素
33     put_list(list1,"list1");
34     put_list(list2,"list2");
35     put_list(list3,"list3");
36     
37     //从list1序列后面添加两个元素
38     list1.push_back(2);
39     list1.push_back(4);
40     cout<<"list1.push_back(2) and list1.push_back(4):"<<endl;
41     put_list(list1,"list1");
42 
43     //从list1序列前面添加两个元素
44     list1.push_front(5);
45     list1.push_front(7);
46     cout<<"list1.push_front(5) and list1.push_front(7):"<<endl;
47     put_list(list1,"list1");
48 
49     //在list1序列中间插入数据
50     list1.insert(++list1.begin(),3,9);
51     cout<<"list1.insert(list1.begin()+1,3,9):"<<endl;
52     put_list(list1,"list1");
53 
54     //测试引用类函数
55     cout<<"list1.front()="<<list1.front()<<endl;
56     cout<<"list1.back()="<<list1.back()<<endl;
57 
58     //从list1序列的前后各移去一个元素
59     list1.pop_front();
60     list1.pop_back();
61     cout<<"list1.pop_front() and list1.pop_back():"<<endl;
62     put_list(list1,"list1");
63 
64     //清除list1中的第2个元素
65     list1.erase(++list1.begin());
66     cout<<"list1.erase(++list1.begin()):"<<endl;
67     put_list(list1,"list1");
68 
69     //对list2赋值并显示
70     list2.assign(8,1);
71     cout<<"list2.assign(8,1):"<<endl;
72     put_list(list2,"list2");
73 
74     //显示序列的状态信息
75     cout<<"list1.max_size(): "<<list1.max_size()<<endl;
76     cout<<"list1.size(): "<<list1.size()<<endl;
77     cout<<"list1.empty(): "<<list1.empty()<<endl;
78 
79     //list序列容器的运算
80     put_list(list1,"list1");
81     put_list(list3,"list3");
82     cout<<"list1>list3: "<<(list1>list3)<<endl;
83     cout<<"list1<list3: "<<(list1<list3)<<endl;
84 
85     //对list1容器排序
86     list1.sort();
87     put_list(list1,"list1");
88     
89     //结合处理
90     list1.splice(++list1.begin(), list3);
91     put_list(list1,"list1");
92     put_list(list3,"list3"); 
93     return 0;
94 }
多花费一些内存来提高性能

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