STL算法find，find_if,find_if_not，sort,fill,for_each，count，adjacent_find，random_shuffle，prev_permutation



1find查找

#include<iostream>

#include<vector>

#include<algorithm>

#include<list>

#include<set>

#include<string>

usingnamespacestd;

voidmain()

{

vector<int>myv;

myv.push_back(1);

myv.push_back(2);

myv.push_back(3);

myv.push_back(11);

myv.push_back(22);

myv.push_back(33);

for_each(myv.begin(),myv.end(),
[](intv){cout
<<v <<endl;
});

auto i
=find(myv.begin(),myv.end(),
23);

//说明已经到了最后面

if
(i ==
myv.end())

{

std::cout
<< "23玩失踪";

}

else

{

//如果找到了则输出结果

std::cout
<< *i;

}

cin.get();

}

运行结果：



2find_if,find_if_not

#include<iostream>

#include<vector>

#include<algorithm>

#include<list>

#include<set>

#include<string>

usingnamespacestd;

voidmain()

{

vector<int>myv;

myv.push_back(1);

myv.push_back(2);

myv.push_back(3);

myv.push_back(11);

myv.push_back(22);

myv.push_back(33);

for_each(myv.begin(),myv.end(),
[](intv){cout
<<v <<endl;
});

std::cout
<< "-------" <<std::endl;

//找到第一个比11大的值

autoii
=find_if(myv.begin(),myv.end(),
[](intv)->bool{return
(v > 11); });

//找到第一个不比4大的值

auto i
=find_if_not(myv.begin(),myv.end(),
[](intv)->bool{return
(v > 4); });

if
(ii ==
myv.end())

{

std::cout
<< "没找到"
<< endl;

}

else

{

std::cout
<< *ii <<endl;

}

std::cout
<< "-------" <<std::endl;

if
(i ==
myv.end())

{

std::cout
<< "玩失踪";

}

else

{

std::cout
<< *i;

}

cin.get();

}

运行结果是：



3sort,fill,for_each

#include<iostream>

#include<vector>

#include<algorithm>

#include<list>

#include<set>

#include<string>

usingnamespacestd;

template <classT>

classshow

{

public:

void
operator()(T &t)

{

cout
<<t <<" ";

}

};

voidmain()

{

list<int>list1;

vector<int>v1;

list1.push_back(121);

list1.push_back(12);

list1.push_back(122);

list1.push_back(23);

v1.push_back(121);

v1.push_back(12);

v1.push_back(122);

v1.push_back(17);

v1.push_back(23);

//list不能通过sort进行排序，如果放开这一句将出现错误

//sort(list1.begin(), list1.end());

//排序，简单的排序

sort(v1.begin(),v1.end());

//算法依赖于数据结构（链式，线性），不同的数据结构，算法不一样

//填充，指定位置数据进行初始化,将begin()+2到最后的数值填充为3

fill(v1.begin()
+ 3, v1.end(),
3);

for_each(list1.begin(),list1.end(),show<int>());

cout
<<"\n";

for_each(v1.begin(),v1.end(),show<int>());

cin.get();

}

运行结果：



4.count,统计某个节点值相同的元素有多少个

#include<iostream>

#include<vector>

#include<algorithm>

#include<list>

#include<set>

#include<string>

usingnamespacestd;

voidmain()

{

multiset<int
> myset;

myset.insert(3);

myset.insert(1);

myset.insert(2);

myset.insert(1);

myset.insert(2);

myset.insert(1);

myset.insert(2);

myset.insert(1);

myset.insert(1);

myset.insert(1);

cout
<<"统计总共的节点"
<< endl;

inti
= 0;

for
(autoib
=myset.begin(),ie
=myset.end();ib
!=ie;ib++,i++)

{}

cout
<<i <<endl;

//统计有多少个节点1

cout
<<"统计值为1的节点个数有多少个"
<< endl;

intnum
=count(myset.begin(),myset.end(),
1);

cout
<<num <<endl;

cin.get();

}

运行结果：



5. adjacent_find，依次打印出结果：

#include<iostream>

#include<vector>

#include<algorithm>

#include<list>

#include<set>

#include<string>

usingnamespacestd;

template <classT>

classshow

{

public:

void operator
()(T &t)

{

cout
<<t <<" ";

}

};

voidmain()

{

multiset<int
> myset;

myset.insert(3);

myset.insert(1);

myset.insert(2);

myset.insert(1);

myset.insert(2);

myset.insert(1);

myset.insert(2);

for_each(myset.begin(),myset.end(),show<constint>());

//通过这种方式一个个的打印出结果

autoit
=adjacent_find(myset.begin(),myset.end());

cout
<<"\n" << *it
<<endl;

it++;

cout
<<"\n" << *it
<<endl;

it++;

cout
<<"\n" << *it
<<endl;

it++;

cout
<<"\n" << *it
<<endl;

//查找相同的数据，可以自己确定位置

it
=adjacent_find(it,myset.end());

cout
<<"\n" << *it
<<endl;

it++;

cout
<<"\n" << *it
<<endl;

it++;

cout
<<"\n" << *it
<<endl;

it++;

cout
<<"\n" << *it
<<endl;

cin.get();

}

运行结果：



6. random_shuffle实现随机排序

#include<iostream>

#include<vector>

#include<algorithm>

#include<list>

#include<set>

#include<string>

usingnamespacestd;

template <classT>

classshow

{

public:

void operator
()(T &t)

{

cout
<<t <<" ";

}

};

voidmain()

{

vector<int>v1;

for
(inti
= 0;i < 10;i++)

{

v1.push_back(i);

}

for_each(v1.begin(),v1.end(),show<int>());

cout
<<"\n";

//通过random_shuffle的方式实现随机排序vector

random_shuffle(v1.begin(),v1.end());

for_each(v1.begin(),v1.end(),show<int>());

cout
<<"\n";

random_shuffle(v1.begin(),v1.end());

for_each(v1.begin(),v1.end(),show<int>());

cout
<<"\n";

random_shuffle(v1.begin(),v1.end());

for_each(v1.begin(),v1.end(),show<int>());

cin.get();

}

运行结果：



用途：随机洗牌

7. partition分区

#include<iostream>

#include<vector>

#include<algorithm>

usingnamespacestd;

template <classT>

classshow

{

public:

void operator
()(T &t)

{

cout
<<t <<" ";

}

};

boolisok(intnum)

{

return
(num >= 10);

}

voidmain()

{

vector<int>v1;

v1.push_back(20);

v1.push_back(23);

v1.push_back(6);

v1.push_back(27);

v1.push_back(5);

v1.push_back(67);

v1.push_back(10);

v1.push_back(13);

v1.push_back(14);

v1.push_back(3);

for_each(v1.begin(),v1.end(),show<int>());

//服务于快速排序的分区

partition(v1.begin(),v1.end(),isok);

cout
<<"\n";

cout
<<endl;

for_each(v1.begin(),v1.end(),show<int>());

cin.get();

}

运行结果：



分析，本质：



8. prev_permutation查看排序过程

#include<iostream>

#include<vector>

#include<algorithm>

usingnamespacestd;

voidmain()

{

inta[4]
= { 2, 1, 3, 10 };

do

{

cout
<<a[0] <<"
" <<a[1]
<<" " <<a[2]
<<" " <<a[3]
<<"\n";

//通过下面这个代码查看排序过程

}
while (prev_permutation(a,a+4));

cin.get();

}

运行结果：



9.sort排序

#include<iostream>

#include<vector>

#include<algorithm>

usingnamespacestd;

template <classT>

classshow

{

public:

void operator
()(T &t)

{

cout
<<t <<" ";

}

};

voidmain()

{

vector<char>myvector;

myvector.push_back('B');

myvector.push_back('A');

myvector.push_back('C');

myvector.push_back('Y');

myvector.push_back('Z');

myvector.push_back('X');

for_each(myvector.begin(),myvector.end(),show<char>());

//sort(one.begin(), one.begin() + 3);

sort(myvector.begin(),myvector.begin()
+ 3);

cout
<<"\n";

for_each(myvector.begin(),myvector.end(),show<char>());

cin.get();

}

运行结果：



10. partial_sort部分排序

#include<iostream>

#include<vector>

#include<algorithm>

#include<list>

#include<set>

#include<string>

usingnamespacestd;

classstudent

{

public:

stringname;

intscore;

public:

student(stringstr,intnum)
:name(str),score(num)

{

}

bool
operator <(conststudent
&s1)const

{

returnthis->score
< s1.score;

}

};

intmain()

{

vector<student>ss;

{

students1("totoA",
106);

ss.push_back(s1);

}

{

students1("totoB",
101);

ss.push_back(s1);

}

{

students1("totoC",
103);

ss.push_back(s1);

}

{

students1("totoD",
105);

ss.push_back(s1);

}

{

students1("totoE",
67);

ss.push_back(s1);

}

{

students1("totoF",
58);

ss.push_back(s1);

}

{

students1("totoG",
111);

ss.push_back(s1);

}

//部分排序

partial_sort(ss.begin(),ss.begin()
+ 4, ss.end());//部分排序

for
(inti
= 0;i < 7;i++)

{

std::cout
<< ss[i].name
<< ss[i].score
<< "\n";

}

cin.get();

}

运行结果：