/* Ajith - Syntax Higlighter - End ----------------------------------------------- */

3.14.2013

Divide a number by 3 without using any arithmetic operators

How to divide a number by 3 without using operators + - / * %

NOTE: I am just trying to collect various answers down in this post available across multiple sites in internet as mentioned in references.

Solution 01:
#include <stdio.h>
#include <stdlib.h>

int main()
{
    FILE *fp=fopen("temp.dat","w+b");
    int number=12346;
    int divisor=3;
    char *buf = calloc(number,1);
    fwrite(buf,number,1,fp);
    rewind(fp);
    int result=fread(buf,divisor,number,fp);
    printf("%d / %d = %d", number, divisor, result);
    free(buf);
    fclose(fp);
    return 0;
}

3.13.2013

Checking Balance of Symbols in a expression

This article is part of article series - "Datastructures"

A balanced expression contains right number of closing and open braces.

For example:

  • [[ - unbalanced expression
  • []{}() - balanced expression
  • [(*)] - balanced expression

Let us see how to find if an expression is balanced or not by checking for following operators [ ] { } and ( ) in the given expression.

Using Stacks



2.05.2013

Conversion from Infix to Postfix

This article is part of article series - "Datastructures"

Converting a Fully Parenthesized Infix expression into Postfix expression  


Analysis:

Five types of input characters

  • Opening parentheses
  • Operands
  • Operators
  • Closing parentheses
  • New line character (\n)

Pseudocode:


********************************************************  
 Function  : main  
  
 Calls     : createStack  
             freeStack                
             pushIntoStack   
             popFromStack   
  
 Called by : NONE   
  
 Input   
 Parameters: Accepts input expression for processing  
    
 Returns   : Converts Fully paranthesized INFIX 
             expression into POSTFIX expression
******************************************************** 

SET i to 0
GET infix expression from user into input_array
SET var with input_array[i]

CALL createStack

WHILE var != end of string

  IF var equals to '(' THEN
  
    CALL pushIntoStack (stack, var)  

  ELSE IF var is a number THEN        
  
    PRINT var  

  ELSE IF var is an arithmetic operator THEN
  
    CALL pushIntoStack (stack, var) 
    
  ELSE IF var equals to ')' THEN

    WHILE stackTop != '('

      IF stackTop is an arithmetic operator THEN

        PRINT stackTop
        popFromStack (stack)

      ENDIF
    
    ENDWHILE

    popFromStack (stack)

  ENDIF

  SET var with input_expression[INCREMENT i]

ENDWHILE

CALL freeStack (stack)

12.25.2012

Deleting a Node from a Singly Linked List

This article is part of article series - "Datastructures"

Previous Article: Implementation of Singly Linked List.
Next Article: Reversing a Singly Linked List

Deletion of a Node from a Singly Linked List
Similar to insertion we have three cases for deleting a Node from a Singly Linked List.

  • Deleting First Node in Singly Linked List

    To complete deletion of firstNode in the list we have to change Head pointing to Next of firstNode.

    Pseudocode:
    firstNode = Head
    
    Head = firstNode->Next
    
    free firstNode
    Complexity:
    Time Complexity: O(1)
    Space Complexity: O(1)

Detecting First Node in a Loop in the List

This article is part of article series - "Datastructures"

Previous Article: Detecting a Loop in Singly Linked List - Tortoise and Hare.
Next Article: Finding Nth node from end of a Singly Linked List.

Once we confirm that there is a Loop in a Singly Linked List we will see how to determine first node of the loop.