分享程序员开发的那些事...
更新时间：2022-09-04 17:16:23
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：