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Python List Comprehension

Way to create a new list from iterable by transforming the items . Syntax: [ output_expression for item in iterable [ conditions ] ] numbers = [1, 2, 3, 4, 5, 6] squares = [number**2 for number in numbers] print(squares) #Output: [1, 4, 9, 16, 25, 36] Using if condition We can use if condition to filter out some elements. numbers = [1, 2, 3, 4, 5, 6] squares = [number**2 for number in numbers if number > 2] print(squares) #Output: [9, 16, 25, 36] Using multiple if condition (ANDing) We can use multiple if conditions to filter out elements. All if conditions will be ANDed numbers = [1, 2, 3, 4, 5, 18, 30] list_1 = [number for number in numbers if number % 2 == 0 if number % 3 == 0] print(list_1) #Output: [18, 30] Using ‘in’ statement (ORing) 'in' keyword can be used to create a condition statement. numbers = [1, 2, 3, 4, 5, 18, 30] list_2 = [number for number in numbers if number % 3 in (1, 2)] print(list_2) #Output: [1, 2, 4, 5]
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Link List

In computer science, a linked list is a linear collection of elements, called nodes, each node have info field and next field pointing to the next node by means of a pointer. It is a data structure consisting of a group of nodes in sequence and connected with links. In simplest form of this data structure, each node is consist of data and a reference (in other words, a link) to the next node in the sequence. This structure allows for efficient insertion or removal of elements from any position in the sequence during iteration. Types of Link List Singly Link List: Insert node at first position in singly link list Insert node at last position in singly link list Insert node at specific position in singly link list Delete node at first position in singly link list Delete node at last position in singly link list Delete node at specific position in singly link list Find number of nodes in singly link list Dublication of singly link list Concatenation of two singly link list So

Insert node at last position in circular doubly link list

Now we will see how to insert a new node at the last position of doubly link list. Algorithm for insertion at last position in circular doubly link list: In this algorithm, START is pointer to first node of list and PTR is the node to be inserted at last. The steps are as follows: Create new node PTR Set the info field of PTR If list is empty i.e. START == NULL Set START = PTR Set PTR->PREV = PTR Set PTR->NEXT = PTR Else Set PTR->NEXT = START Set PTR->PREV = START->PREV Set START->PREV->NEXT = PTR Set START->PREV = PTR End If; Function to insert node at last position in circular doubly link list: void insertAtLast(NODE **start, int info){ NODE *ptr = (NODE*) malloc(sizeof(NODE)); ptr->info = info; if(*start == NULL){ *start = ptr; ptr->next = ptr; ptr->prev = ptr; } else{ ptr->next = *start; ptr->prev = (*start)->prev; (*start)->prev->next = ptr; (*start)->prev = ptr; } } Program to insert a

Insert node at last position in doubly link list

Now we will see how to insert a new node at the last position of doubly link list. Algorithm for insertion at last position in doubly link list: In this algorithm, START is pointer to first node of list and PTR is the node to be inserted at last. The steps are as follows: Create new node PTR Set the info field of PTR Set PTR->NEXT = NULL If list is empty i.e. START == NULL Set START = PTR Set PTR->PREV = NULL Else Traverse the list for last node into TEMP pointer Set PTR->PREV = TEMP Set TEMP->NEXT = PTR End If;     Function to insert node at last position in doubly link list: void insertAtLast(NODE **start, int info){ NODE *ptr = (NODE*) malloc(sizeof(NODE)); NODE *temp = *start; ptr->info = info; ptr->next = NULL; if(*start == NULL){ *start = ptr; ptr->prev = NULL; } else{ while(temp->next != NULL){ temp = temp->next; } ptr->prev = temp; temp->next = ptr; } }   Program to insert at last position in the do

Circular Doubly Link List

Circular Doubly Link List is data structure which contains a list of node containing info part and links to the next and previous node. In CDLL, last node's next pointer points to the first node and first node's previous pointer points to last node of the list. This  makes traversal in both direction of CDLL.  Before going to discuss the operation on circular doubly link list, we will first see the basic structure of the data type and see how it could be represented in c programming. First we will see the how the node or element of circular doubly link list is represented. See the image below: The component of circular doubly list node: info : It contains the actual information next : This field points to the next node in the list prev  : This field points to the previous node in the list Now we see how the circular doubly link list is represented. See the image below: The component of circular doubly link list are: START  pointer points to the first node of the lis

Doubly Link List

Doubly Link List is data structure which contains list of node having info part and pointer to previous and next node of the list. This makes traversal easy. The last node's next and first node's prev pointer points to nothing. Before going to discuss the operation on doubly link list, we will first see the basic structure of the data type and see how it could be represented in c programming. First we will see the how the node of doubly link list is represented. See the image below: The component of singly list node: info : It contains the actual information next : This field points to the next node in the list prev  : This field points to the previous node in the list Now we see how the doubly link list is represented. See the image below: The component of doubly list are: START  pointer points to the first node of the list NODE : Each node have info field, next pointer to point next NODE in the list and prev pointer to point previous node in the list prev o

Prefix to Infix Conversion

With a given Prefix Expression, we will see how to convert Prefix Expression into Infix Expression using stack.   Algorithm to convert Prefix Expression to Infix Expression: In this algorithm, we will use stack to store operands during the conversion. The step are as follows: Read the prefix string While the end of prefix string scanned from right to left symb = the current character If symb is an operator poped_sym1 = pop the stack poped_sym2 = pop the stack concat the string  STR = ( poped_sym1 )+ ( operator )+( poped_sym2 ) push the string STR into stack Else push the operand symb into stack End If End While infix_str = pop the stack   Function to convert Prefix Expression to Infix Expression: void prefix_to_infix(char prefix[], char infix[]){ char op[2]; //operator string char poped1[MAX]; char poped2[MAX]; char temp[MAX]; int i = strlen(prefix); op[1] = '\0'; while(--i != -1){ if(prefix[i] == ' '){ continue; } if(isoper