侯捷STL学习(二)

第六节：容器之分类和各种测试（四）

stack不提供iterator操作，破坏了容器的独特性，先进先出。

使用容器multiset（允许元素重复）

内部是红黑树，insert操作就保证了排好了序。
标准库有个：：find()函数，大家都可以用。容器本身也有一个c.find()，通过键值对查找非常快！
测试

#include <set>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj06

{

void test_multiset(long& value)

{

	cout << "\ntest_multiset().......... \n";

multiset<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.insert(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "multiset.size()= " << c.size() << endl;

	cout << "multiset.max_size()= " << c.max_size() << endl;	//214748364

string target = get_a_target_string();

	{

    timeStart = clock();

auto pItem = find(c.begin(), c.end(), target);	//比 c.find(...) 慢很多

	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

 	}

 	{

    timeStart = clock();

auto pItem = c.find(target);		//比 std::find(...) 快很多

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

 	}	

	c.clear();

	test_moveable(multiset<MyString>(),multiset<MyStrNoMove>(), value);

}

}

使用容器multimap（允许元素重复）

内部是红黑树，key-value键值对。
multiset不可用[]做insertion
c.insert(pair<long,string>(i,buff))
(*pItem).second
测试

#include <map>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj07

{

void test_multimap(long& value)

{

	cout << "\ntest_multimap().......... \n";

multimap<long, string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

    		//multimap 不可使用 [] 做 insertion

        	c.insert(pair<long,string>(i,buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "multimap.size()= " << c.size() << endl;

	cout << "multimap.max_size()= " << c.max_size() << endl;	//178956970	

long target = get_a_target_long();

    timeStart = clock();

auto pItem = c.find(target);

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, value=" << (*pItem).second << endl;

  	else

    	cout << "not found! " << endl;	  

	c.clear();

}

}

使用unordered_multiset容器

使用hashtable使用分离链地址方法实现
gnu C之前的名称hash_multiset
unorder_multiset.bucket_count篮子的个数
load_factor,max_load_factor,max_bucket_count方法
篮子后面的链表不能太长，元素的个数大于等于篮子的个数，就需要重新分配篮子的大小，重新进行插入元素
c.find()容器自身的find操作快很多
测试

#include <unordered_set>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj08

{

void test_unordered_multiset(long& value)

{

	cout << "\ntest_unordered_multiset().......... \n";

unordered_multiset<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.insert(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "unordered_multiset.size()= " << c.size() << endl;

	cout << "unordered_multiset.max_size()= " << c.max_size() << endl;	//357913941

	cout << "unordered_multiset.bucket_count()= " << c.bucket_count() << endl;

	cout << "unordered_multiset.load_factor()= " << c.load_factor() << endl;

	cout << "unordered_multiset.max_load_factor()= " << c.max_load_factor() << endl;

	cout << "unordered_multiset.max_bucket_count()= " << c.max_bucket_count() << endl;

  	for (unsigned i=0; i< 20; ++i) {

    	cout << "bucket #" << i << " has " << c.bucket_size(i) << " elements.\n";

  	}					

string target = get_a_target_string();

	{

    timeStart = clock();

auto pItem = find(c.begin(), c.end(), target);	//比 c.find(...) 慢很多

	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

 	}

 	{

    timeStart = clock();

auto pItem = c.find(target);		//比 std::find(...) 快很多

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

 	}		

    c.clear();

	test_moveable(unordered_multiset<MyString>(),unordered_multiset<MyStrNoMove>(), value);

}

}

使用unordered_multimap容器

测试

#include <unordered_map>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj09

{

void test_unordered_multimap(long& value)

{

	cout << "\ntest_unordered_multimap().......... \n";

unordered_multimap<long, string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

			//multimap 不可使用 [] 進行 insertion

			c.insert(pair<long,string>(i,buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "unordered_multimap.size()= " << c.size() << endl;

	cout << "unordered_multimap.max_size()= " << c.max_size() << endl;	//357913941	

long target = get_a_target_long();

    timeStart = clock();

auto pItem = c.find(target);

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, value=" << (*pItem).second << endl;

  	else

    	cout << "not found! " << endl;

}

}

使用set容器

不允许元素重复

#include <set>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj13

{

void test_set(long& value)

{

	cout << "\ntest_set().......... \n";

set<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.insert(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "set.size()= " << c.size() << endl;

	cout << "set.max_size()= " << c.max_size() << endl;	   //214748364

string target = get_a_target_string();

	{

    timeStart = clock();

auto pItem = find(c.begin(), c.end(), target);	//比 c.find(...) 慢很多

	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

 	}

 	{

    timeStart = clock();

auto pItem = c.find(target);		//比 std::find(...) 快很多

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

 	}

}

}

使用map容器

不允许元素键重复
c[i]=string(buf)组成pair，允许这样进行插入操作

#include <map>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj14

{

void test_map(long& value)

{

	cout << "\ntest_map().......... \n";

map<long, string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

			c[i] = string(buf);

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "map.size()= " << c.size() << endl;

	cout << "map.max_size()= " << c.max_size() << endl;		//178956970

long target = get_a_target_long();

    timeStart = clock();

auto pItem = c.find(target);

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, value=" << (*pItem).second << endl;

  	else

    	cout << "not found! " << endl;			

    c.clear();

}

}

使用unorder_set容器

#include <unordered_set>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj15

{

void test_unordered_set(long& value)

{

	cout << "\ntest_unordered_set().......... \n";

unordered_set<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.insert(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "unordered_set.size()= " << c.size() << endl;

	cout << "unordered_set.max_size()= " << c.max_size() << endl;  //357913941

	cout << "unordered_set.bucket_count()= " << c.bucket_count() << endl;

	cout << "unordered_set.load_factor()= " << c.load_factor() << endl;

	cout << "unordered_set.max_load_factor()= " << c.max_load_factor() << endl;

	cout << "unordered_set.max_bucket_count()= " << c.max_bucket_count() << endl;

  	for (unsigned i=0; i< 20; ++i) {

    	cout << "bucket #" << i << " has " << c.bucket_size(i) << " elements.\n";

  	}			

string target = get_a_target_string();

	{

    timeStart = clock();

auto pItem = find(c.begin(), c.end(), target);	//比 c.find(...) 慢很多

	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

 	}

 	{

    timeStart = clock();

auto pItem = c.find(target);		//比 std::find(...) 快很多

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

 	}

}

}

使用unorder_map容器

#include <unordered_map>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj16

{

void test_unordered_map(long& value)

{

	cout << "\ntest_unordered_map().......... \n";

unordered_map<long, string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

			c[i] = string(buf);

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "unordered_map.size()= " << c.size() << endl;	//357913941

	cout << "unordered_map.max_size()= " << c.max_size() << endl;	

long target = get_a_target_long();

    timeStart = clock();

//! auto pItem = find(c.begin(), c.end(), target);	//map 不適用 std::find()

auto pItem = c.find(target);

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;

	if (pItem != c.end())

    	cout << "found, value=" << (*pItem).second << endl;

  	else

    	cout << "not found! " << endl;

}

}

hash_set/hash_map/hash_multiset/hash_multimap

包含gnu C的编译器就可以
包含的头文件可能需要修改#include<...>非标准容器，由于时间的原因，没有放在一起,在C++11大会之前就出现了！
测试

/*

以下測試 hash_multiset, hash_multimap 過程中遇到阻礙：

headers <hash_set> 和 <hash_map> 各有兩個，

分別在 ...\4.9.2\include\c++\backward 和 ...\4.9.2\include\c++\ext，

不知要用哪一組!

用 <ext\...> 那一組會有問題

   ...\4.9.2\include\c++\backward\hashtable.h

   [Error] no match for call to '(const hasher {aka const __gnu_cxx::hash<std::basic_string<char> >}) (const key_type&)'

用 <backward\...> 那一組有相同的問題.

so, 放棄測試 (no insertion or push_back or ...).

*/

#include <ext\hash_set>

    //...\4.9.2\include\c++\backward\backward_warning.h

	//[Warning] #warning This file includes at least one deprecated or antiquated header

	//which may be removed without further notice at a future date.

	//Please use a non-deprecated interface with equivalent functionality instead.

	//For a listing of replacement headers and interfaces, consult the file backward_warning.h.

	//To disable this warning use -Wno-deprecated. [-Wcpp]

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj11

{

void test_hash_multiset(long& value)

{

	cout << "\ntest_hash_multiset().......... \n";

	__gnu_cxx::hash_multiset<string> c;

	char buf[10];

    clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	//! c.insert(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

}

}

//---------------------------------------------------

#include <ext\hash_map>

    //...\4.9.2\include\c++\backward\backward_warning.h

	//[Warning] #warning This file ... (如上個函數所言)

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj12

{

void test_hash_multimap(long& value)

{

	cout << "\ntest_hash_multimap().......... \n";

	__gnu_cxx::hash_multimap<long, string> c;

	char buf[10];

    clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	//c.insert(...

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;		

    timeStart = clock();

    //! auto ite = c.find(...

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

}

}

侯捷STL学习(二)的更多相关文章

侯捷STL学习(二)--序列容器测试
第六节:容器之分类和各种测试(四) stack不提供iterator操作,破坏了容器的独特性,先进先出. 使用容器multiset(允许元素重复) 内部是红黑树,insert操作就保证了排好了序. 标 ...
侯捷STL学习(九)--关联式容器(Rb_tree,set,map)
layout: post title: 侯捷STL学习(九) date: 2017-07-21 tag: 侯捷STL --- 第十九节容器rb_tree Red-Black tree是自平衡二叉搜索 ...
侯捷STL学习(12)--STL相关内容hash+tuple
layout: post title: 侯捷STL学习(12) date: 2017-08-01 tag: 侯捷STL --- 第四讲 STL相关的内容 Hash Function 将hash函数封装 ...
侯捷STL学习(11)--算仿+仿函数+适配器
layout: post title: 侯捷STL学习(十一) date: 2017-07-24 tag: 侯捷STL --- 第三讲标准库内核分析-算法标准库算法形式 iterator分类不同 ...
侯捷STL学习(十)--容器hashtable探索(unordered set/map)
layout: post title: 侯捷STL学习(十) date: 2017-07-23 tag: 侯捷STL --- 第二十三节容器hashtable探索 hashtable冲突(碰撞)处理 ...
侯捷STL学习(八)-- 深度探索deque
layout: post title: 侯捷STL学习(八) date: 2017-07-19 tag: 侯捷STL --- 第十八节深度探索deque上 duque内存结构分段连续,用户看起来是 ...
侯捷STL学习(七)--深度探索vector&&array
layout: post title: 侯捷STL学习(七) date: 2017-06-13 tag: 侯捷STL --- 第十六节深度探索vector vector源码剖析 vector内存2倍 ...
侯捷STL学习(一)
开始跟着<STL源码剖析>的作者侯捷真人视频,学习STL,了解STL背后的真实故事! 视频链接:侯捷STL 还有很大其他视频需要的留言第一节:STL版本和重要资源 STL和标准库的区别 ...
侯捷STL学习(一)--顺序容器测试
开始跟着<STL源码剖析>的作者侯捷真人视频,学习STL,了解STL背后的真实故事! 视频链接:侯捷STL 还有很大其他视频需要的留言第一节:STL版本和重要资源 STL和标准库的区别 ...

随机推荐

Java高级特性（基础）
1.StringBuffer.StringBuilder和String一样,也用来代表字符串.String类是不可变类,任何对String的改变都会引发新的String对象的生成:StringBuf ...
C# 类型转换is和as 以及性能陷阱
1.在C#2.0之前,as只能用于引用类型.而在C#2.0之后,它也可以用于可空类型.其结果为可空类型的某个值---空值或者一个有意义的值.示例: static void Main(string ...
【从无到有】JavaScript新手教程——1.简介、变量和运算符
今天带大家来学习一下在网页制作过程中很常用的JavaScript(简称JS). 一.JS的作用: 表单验证,减轻服务端的压力添加页面动画效果动态更改页面内容 Ajax网络请求二.[使用JS的 ...
CF #345 Div1 D Zip-line
题目链接:http://codeforces.com/contest/650/problem/D 大意是给一个数组,若干询问,每一次把一个数字改为另一个数字,问当前数组最长上升子序列,询问之间是独立的 ...
onmouseover事件
根据教学视频写了个onmouseover事件: <!DOCTYPE html> <html> <head> <meta charset="UTF-8 ...
c标签和foreach循环不能加载
需要同时导入2个包: jstl.jar和standard.jar(大多数时候只会注意到jstl包,而忽视了standard包) 代码: c标签的写法 <%@ taglib prefix=&quo ...
qt中字符串转换
11.各种数据类型的相互转换char * 与 const char *的转换char *ch1="hello11";const char *ch2="hello22&qu ...
学习Java之前操作环境的安装及配置
1.根据自己的系统版本下载相应版本的JDK(Java开发运行时环境) 查看自己系统版本的方法:在桌面上右键计算机(win7,win10是此电脑,XP是我的电脑),点击属性,进入到计算机属性页面以后里面 ...
collection and map and Collections
两者的区别: 两者都是接口: Collectoin是java集合框架的一个顶级接口,存储的元素可以是任意类型的对象: Map是java集合框架的映射接口,以键值对的形式存储对象: 也就是说,colle ...
jdbc ,jdbcTemplate,MyBatis,Hibernate比较与分析
JDBC 1:jdbc(Java Data Base Connection 数据库连接)是一种用于执行sql语句的API,其中使用jdbc连接时需要的,Connection,Statement,Res ...

侯捷STL学习(二)

第六节：容器之分类和各种测试（四）

使用容器multiset（允许元素重复）

使用容器multimap（允许元素重复）

使用unordered_multiset容器

使用unordered_multimap容器

使用set容器

使用map容器

使用unorder_set容器

使用unorder_map容器

hash_set/hash_map/hash_multiset/hash_multimap

侯捷STL学习(二)的更多相关文章

随机推荐

热门专题