C + + BASIC data structure collation

Hash Map (unordered_map)

• Insert
  

  #include <unordered_map>usingnamespace<charbool>  Hash_map;hash_map.insert (Make_pair<char,bool> ('a', true));

• Find
  

  if (Hash_map.find (num) =="notfound" << Endl;
  Unordered_map <char, bool>:: Iterator got = Hash_map.find (' a ');
  Got->first point to Key
  Got->second point to Value

String

2. How to traverse each element in a string
   

   // SA is a string  for string:: iterator p = sa.begin (); P!= Sa.end (); p++ )         << *p;      << Endl;

4. How to use the Find in string

   string: Size_type pos = str.find ('0');        // POS is the position in string you find. if (pos==string::"cannt find"; Else  << pos;

Type Conversion

1. Char-Int
   

   char s = ' 5 ' int a = s ' 0 ';

2. String Int
   

   string s = std::to_string (5);

3. String-Int
   

   std::string""; int //

4. You Cann ' t-switch-case statement on string by C + +

   
   

Stack

2. How to press into a pair
   

   int> > s;s.push (Make_pair (Root,1*tmp = s.top (). int len = S.top (). Second;

3. With the push () in the STL stack, Pop (), Top ()

   //STL Stack adapters (stacks)#include <iostream>#include<stack>using namespacestd;intMain () {stack<int> is;//Defining Stack Objects   for(inti =0; I < -; ++i) is. Push (i+ -);//100~199 the stack in a single ordercout<<"Top element:"<< is. Top () <<endl;//view top of stack elements  is. Pop ();//out of stack operationcout<<"new top element:"<< is. Top () <<endl;//view top of stack elementscout<<"Size:"<< is. Size () <<endl;//View Stack Height  return 0; } 

Heap

• How to use existing data structures to implement heap operations including Push_head, Pop_head, Sort_heap
  

  //Range Heap Example#include <iostream>//Std::cout#include <algorithm>//std::make_heap, std::p op_heap, std::p ush_heap, Std::sort_heap#include <vector>//std::vectorintMain () {intMyints[] = {Ten, -, -,5, the}; Std::vector<int> V (myints,myints+5);  Std::make_heap (V.begin (), V.end ()); Std::cout<<"initial max heap:"<< V.front () <<'\ n'; std::p op_heap (V.begin (), V.end ());                 V.pop_back (); //pop_heap () is used to eject the first element in the heap & #65292, and put it in the last position of the interval & #65292, and then re-build the previous element into a heap & #12290;Std::cout <<"Max heap after pop:"<< V.front () <<'\ n'; V.push_back ( About); std::p ush_heap (V.begin (), V.end ());//push_heap () is used to add the last element of the specified interval to the heap and make the entire interval a new heap & #12290; Note that all elements except the last element already constitute a heap & #12290;Std::cout <<"Max Heap after push:"<< V.front () <<'\ n';  Std::sort_heap (V.begin (), V.end ()); Std::cout<<"final sorted Range:";  for(Unsigned i=0; I<v.size (); i++) Std::cout<<' '<<V[i]; Std::cout<<'\ n'; return 0;} Output:initial Max Heap: -Max heap after pop: -Max Heap after push: Aboutfinal sorted Range:5 Ten  the  -  About

Array & Vector

• How multidimensional vectors determine the size of rows and columns
  

  vector<vector<int> > matrixint rowsize = matrix.size (); int colsize = matrix[0].size ()

• Inserts an element in front of a specified position using insert ()
  

  #include <iostream>#include<vector>using namespacestd;intmain () {vector<int> V (3); v[0]=2; v[1]=7; v[2]=9; //Insert 8 in front of the front elementV.insert (V.begin (),8); //inserting a new element before the second element 1V.insert (V.begin () +2,1); //Insert a new element at the end 1V.insert (V.end (),3);  for(vector<int>::iterator It=v.begin (); It!=v.end (); it++) cout<<*it<<Endl; System ("Pause"); return 0; }

• The method of finding the smallest element in vector with STL
  

  cout<<"maxinum:"<<*min_element (V.begin (), V.end ()) <<Endl; int index = min_element (V.begin (), V.end ())-v.begin ();

• Create a multidimensional array with vectors. Multidimensional arrays are written as vector<vector<int> spaces;. In fact, a two-dimensional array/matrix A is described. Its initialization can refer to the following code

   std::vector<std::vector<int  > >    A; Vector  < Vector<int  > > INTVV      ;      Vector  <int  > Intv;       int   I,j;  for  (I=0 ; I<10 ; ++i) {intv.clear ();  for  (J=0 ; J<10 ; ++j) intv.push_back (i  *10  +< Span style= "color: #000000;"        >J); Intvv.push_back (INTV);  

• A simple notation for iterating through an array
  

  int num[] = {2,2,3};      for (int i:num)   // You must define I here.        cout << i << Endl;

• The Pop/push in the vector
  

  #include <vector>using namespace std;vector<char> array;array.push_back (' 9 '); char num = Array.back (); Array.pop_back ();   

STL operator overloading to change the sort algorithm

Sort elements & #65292; object struct person   {person  }    (int id, const string& name, int age ): Id_ (ID), Name_ (name), Age_ (age)    {}        int id_;    String name_;    int age_;  };  Method 1& #65306; operator< used for sorting (written in function body)  bool operator< (const person& RT) {return this-> Id_ <sort (Members.begin (), Members.end ());//mode 2& #65306; write comparison function bool Compage (const person& PL, const person& PR) {return Pl.age_ <sort (Members.begin (), Members.end (), compage);//mode 3& #65306; functor struct Compname {bool operator () (const person& PL, const person& PR) {return Pl.name_ < /c22> 

Definition of data structure in Leetcode

 for singly-struct*     int*     listnode **     ListNode (int**/

C + + BASIC data structure collation