[dark horse programmer C++ STL] learning record

Posted by AchillesForce on Sat, 05 Mar 2022 16:07:30 +0100

Dark horse programmer 2017 C++ STL tutorial (STL part has been completed)

STL course arrangement based on dark horse: Dark horse programmer 2017C++STL tutorial ⬅😊 Video link
special column 😬: Contents of this STL column

Article catalogue

The link is as follows:

special column: Contents of this STL column

1.1 basic concept of STL

1.2 simple STL cases

2.2 C++STL ⭐ string container details
String is a C + + style string. In terms of early algorithm competition, cstring in C language style is enough??? (style of being y always taken) 😛)

2.3 C++STL ⭐ vector container details
Dynamic array

2.4 detailed explanation of C + + STL deque container
Double ended array, operation characteristics: the efficiency of inserting and deleting at both ends is particularly high. Inserting at the specified position will also cause the movement of data elements, and random access is supported.

2.5 C++STL ⭐ Detailed explanation of stack
Rule: first in, then out.
Traversal does not provide iterators or support random access.

while(!stack.empty())//Traversal mode

2.6 C++STL ⭐ queue details
Rule: first in, first out
Cannot traverse. Iterators are not provided and random access is not supported

while(!queue.empty())//Traversal mode

2.7 C++STL list container details
Very commonly used stl in the two-way linked list
The efficiency of inserting and deleting elements is not good at any time.
Disadvantages: random access is not supported because it costs continuous memory space. Therefore, in order to save the predecessor successor relationship between nodes, additional space overhead is required.

2.8 C++STL ⭐ Detailed explanation of set/multiset container (including pair)

// Team pair combines two values into one value
pair<string,int> pair1;

2.9 detailed explanation of C + + STL map / Multimap container
map is different from set. map has key value and real value, and all elements are sorted automatically according to the key value. The first element of pair is called the key value, and the second element is called the real value. map also takes red black tree as the underlying implementation mechanism.

Overview of related API s

STL relevant API summary
   vector, Variable length array, multiplication idea
   	size()  Returns the number of elements
   	empty()  Returns whether it is empty
   	clear()  empty
   	Support comparison operation, in dictionary order

   pair<int, int>
   	first, First element
   	second, Second element
   	Support comparison operation to first Is the first keyword, with second Is the second keyword (dictionary order)

   string,character string
   	szie()/length()  Return string length
   	substr(Starting subscript,(Substring length))  Return substring
   	c_str()  Returns the starting address of the character array where the string is located

   queue, queue
   	push()  Insert an element at the end of the queue
   	front()  Return queue header element
   	back()  Return tail element
   	pop()  Pop up queue header element

   priority_queue, Priority queue. The default is large root heap
   	push()  Insert an element
   	top()  Returns the top of heap element
   	pop()  Pop top element
   	How to define as a small root heap: priority_queue<int, vector<int>, greater<int>> q;

   stack, Stack
   	push()  Insert an element into the top of the stack
   	top()  Return stack top element
   	pop()  Pop up stack top element

   deque, Double ended queue

   set, map, multiset, multimap, Based on balanced binary tree (red black tree), the ordered sequence is maintained dynamically
   	++, -- Return precursor and successor, time complexity O(logn)
   		insert()  Insert a number
   		find()  Find a number
   		count()  Returns the number of a number
   			(1) The input is a number x,Delete all x   O(k + logn)
   			(2) This iterator, delete an input iterator
   			lower_bound(x)  Return greater than or equal to x Iterator of the smallest number of
   			upper_bound(x)  Return greater than x Iterator of the smallest number of
   		insert()  The number of inserts is one pair
   		erase()  The input parameter is pair Or iterator
   		[]   The time complexity is O(logn)

   unordered_set, unordered_map, unordered_multiset, unordered_multimap, Hashtable 
   	Similar to the above, the time complexity of adding, deleting, modifying and querying is O(1)
   	I won't support it lower_bound()/upper_bound(), Iterator++,--

   bitset, Pressure level
   	bitset<10000> s;
   	~, &, |, ^
   	>>, <<
   	==, !=
   	count()  Returns how many 1s there are
   	any()  Determine whether there is at least one 1
   	none()  Judge whether all are 0
   	set()  Set all positions to 1
   	set(k, v)  Will be the first k Bit becomes v
   	reset()  Change all bits to 0
   	flip()  Equivalent to~
   	flip(k) Put the first k Bit inversion
Author: yxc
 Link: https://www.acwing.com/blog/content/404/
Source: AcWing
 The copyright belongs to the author. For commercial reprint, please contact the author for authorization. For non-commercial reprint, please indicate the source.


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