全网统一id:I安全卫队I淡淼 动头像者 均为我普鲁士国之敌 https://www.bilibili.com/video/BV17G4y1c7EY/

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 <-目前全oj最长    9000        | 
.
/*字符串基本输入输出遍历*/ 
	string a;//创建字符串a,默认空串
	string b="";
	cin >> a;//输入不带空格的
	getline(cin,a);//带空格的
	cout << a;//整体输出
	//遍历字符串
	int len = a.size();//返回长度
	for(int i=0;i<=len-1;i++)
	{
		cout << a[i];
	} 
/*字符串可以使用的运算符*/
	+ :拼接字符串 
	= :赋值
	比较运算符 > < >= <= == != 
	string a="abc";
	string b="xyz";
	cout << a+b << endl;//输出abcxyz
	string c = a+b;
	c+=a;
	cout << c << endl;//输出abcxyzabc 
/*字典序*/
	//找到第一个不相同的字符，比较他们的ASCII码值 
	string a="abc";
	string b="aBc";
	if(a>b) cout << 1 ;
	else if(a<b) cout << 2;
	else cout << 0;
/*字符串数组*/
	string a[1005];
	int n;
	cin >> n;
	for(int i=1;i<=n;i++)
	{
		cin >> a[i];
	} 
	sort(a+1,a+1+n)//可以使用排序函数 
	for(int i=1;i<=n;i++)
	{
		cout << a[i] << " ";
	}
.
//十进制转二进制                                  
-5  ->    1000 0101=1111 1010+1=1111 1011              
-13 ->    1000 1101=1111 0010+1=1111 0011
0.625 ->  0.625*2=1.25 0.25*2=0.5 0.5*2=1 =>0.101
13.25 ->  13=1101 0.25*2=0.5 0.5*2=1 =>1101.01
//二进制转十进制
0.011 ->  0*1/2 1*1/4 1*1/8 =>0.375
1001.001->1001=9 1*1/8 =>9.125 

int a=-5 
unsigned int b=a;
cout<<b;
//b=1111 1111 1111 1111 1111 1111 1111 1011=1111 1111 1111 1111 1111 1111 1111 1011-0000 0000 0000 0000 0000 0000 0000 0100=4294967291
0--0--0--0    0.0---0---0     
8  4  2  1    1.1/2 1/4 1/8    
位 位 位 位   _____________   
.                            
.        二 bit   字节       
bool       8       1         
char       8       1         
int        32      2         
float      32      4         
double     64      8         
long long  64      8     
.对于有符号数 
整数最大值2^(位数-1)-1
负数最小值-2^(位数-1) 
.对于无符号数 
unsigned int 全部表示正数 范围是 0 ~ 2^32 ~ -1
unsigned long long 全部表示正数 范围是 0 ~ 2^64 ~ -1
.位运算 
&  按位与   同1则1 
5&3 = 1
	0000 0101 
&	0000 0011
--------------
    0000 0001
    
|  按位或   有1则1 
5|3=7
	0000 0101 
|	0000 0011
--------------
    0000 0111
    
~ 按位取反  01互换 
~5=-6
~	0000 0101
---------------
	1111 1010 [补码]
	1111 1001 [反码]
	1000 0110 [原码] -6
^ 按位异或  不同为1,相同为0 
5^3 = 6
	0000 0101 
^	0000 0011
--------------
    0000 0110
^   0000 0011
--------------
    0000 0101

0^任何数字 = 任何数字


位运算的左移动   二进制整体往左移动，缺位补0 
5<<1 = 10
0000 0101 << 1 
0000 1010


位运算的右移动   二进制整体往右移动，缺位补符号位（正数补0，负数补1） 
5>>1 = 2
0000 0101 >> 1 
0000 0001

左移相当于*2
右移相当于/2 
	 
	 
位运算的优先级很低，使用过程中需要打括号 ，按位取反~ 除外 
.
auto a=1   //整型 
auto b=2.7 //小数 
auto c='z' //字符串
.
二叉堆（优先队列priority_queue） 
父<子：小顶堆（小根堆） 
父>子：大顶堆（大根堆） 

插入的时间复杂度：O(logn) 
删除的时间复杂度：O(logn) 
查询最值的时间复杂度：O(1) 


	创建一个二叉堆
	priority_queue<int,vector<int>,greater<int> > small;//小根堆 
	priority_queue<int,vector<int>,less<int> > big;//大顶堆
	/*
	堆名.push(元素);//插入元素
	堆名.pop();//删除堆顶	 
	堆名.top();//返回堆顶
	堆名.size();//返回二叉堆的大小 
	堆名.empty();//如果二叉堆为空返回1 ，不为空返回0 
	*/