Learn Computer programming for free Online | Code Crow

HackerRank solution in Java || Data structure problem || Hourglass problem of 2-D array

2019-07-04T09:00:00.000+05:30

In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and algorithms in C,Java,Python and other programming languages that may help you land an online job and make your programmers day successful.We use best data structure notes and best programming resources.
Here goes the article,don't forget to share with your friends 👏💘💘
Let We have a 2-D Array of size 6×6.The hourglass of array is of a particular form which we will explained later in this post.For example consider the array below:

1 5 7 8 9 9

7 8 9 9 9 0

8 4 2 8 0 1

5 7 7 2 4 2

7 3 1 9 7 0

The hour glass of an array will be of the form below:

a b c
d
e f g

That means in the matrix we have total 16 hourglass,4 horizentally and 4 vertically.

In this problem we have to find the sum of the hourglass which have the maximum sum among other hourglasses.

Solution :

public class Solution {

    // The hourglass sum

    static int Sum(int[][] a) {

        int max = -1000; // As sum sum can be negative

        for(int i=0;i<4;i++) // Because there are 4 hourglass horizontally

        {

            for(int j=0;j<4;j++) // Because there are 4 hourglass vertically

            {

                if((a[i][j]+a[i][j+1]+a[i][j+2]

+a[i+1][j+1]+a[i+2][j]+a[i+2][j+1]+a[i+2][j+2])>max)

                    max=a[i][j]+a[i][j+1]+a[i][j+2]+a[i+1][j+1]

+a[i+2][j]+a[i+2][j+1]+a[i+2][j+2];

            }

        }

        return max;

    }

Here I given only the function which will calculate the maximum hourglass sum.
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Geeks For Geeks problem|| Rotating an Array

2019-06-25T21:06:00.000+05:30

Geeks For Geeks have many meticulous problems in their bag,and for any programming enthusiasts it is pleasure to solve them. In our previous post I solved one of the problems you can check it out here.
Like our previous post I again want to mention that I am not doing any promotion here,I just love to solve their problems as a code lover.
In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and algorithms in C,Java,Python and other programming languages that may help you land an online job and make your programmers day successful.We use best data structure notes and best programming resources.
Here goes the article,don't forget to share with your friends.
Let us begin with the problem:
Problem Statement: Let we have T number of testcases. For each testcase we have an array of size N.Now we have to rotate the array by d elements.The first line of input contains
the number of testcase T,the second line contains the size of the array N,third line contains N space separated integers and fourth line contains d.
Example:
Input:
2
5
1 2 3 4 5
2
1
4
1
Output:
3 4 5 1 2
4
Solution:
#include <stdio.h>

main() {
int a[1000],i,j,k,N,d,T;
scanf("%d",&T); //Taking Number of testcases
while(T--)
{
scanf("%d",&N); // Taking size of array
for(i=0;i<N;i++)
scanf("%d",&a[i]); //Taking array
scanf("%d",&d);
for(j=d;j<N;j++) //printing the elements from skipping d elements to last element
{
printf("%d ",a[j]);
}
for(k=0;k<d;k++)
printf("%d ",a[k]); //printing 1st d elements after printing the elements of previous segment
printf("\n");
}

return 0;

}

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Geeks For Geeks problem || Finding the immediate small element

2019-06-25T09:00:00.000+05:30

Geeks for Geeks is very popular and helpful website for Computer Science students,they have an excellent collection of questions related to coding,interview experiences and so on.
In this article we will solve a array related problem in which we are given an an array and we have to print the next element of each element if the element is small than the previous element otherwise we have to print -1.
In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and algorithms in C,Java,Python and other programming languages that may help you land an online job and make your programmers day successful.We use best data structure notes and best programming resources.
Here goes the article,don't forget to share with your friends 😊😊
Let me very clear before we going to solve the problem that I am not doing any promotion of Geeks For Geeks its just that I love problem solving from this kind of websites and I also recommend you to do so.Enough talking though lets jump on to the problem -------
Problem Statement: Let we have T testcases. For each case we have an array of given size.For each array we have to print the next element of each element if the next element is smaller than the previous element otherwise we will print -1.
The first line of input is T=number of testcase;each testcase have 2 lines of input,
first line is the size of the array,and the second line is the elements separated by space.
Example:
Input:
2
5
1 3 2 7 2
4
8 5 9 2
Output:
-1 2 -1 -1
5 -1 2 -1
Solution:
#include <stdio.h>
main() {
int T,N,a[100000],i;
scanf("%d",&T); // Taking input of number of test cases
while(T--)
{
scanf("%d",&N); //Taking input of size of the array for each testcase
//Taking input of the array
for(i=0;i<N;i++)
scanf("%d",&a[i]);

for(i=0;i<N-1;i++)
{
//Check wheather the next element is smaller than the previous element upto the 2nd last element
if(a[i]>a[i+1])
printf("%d ",a[i+1]);
else
printf("-1 ");
}
//Print -1 for the last element as it has no element to compare with
printf("-1");
printf("\n");
}

return 0;
}

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How to represent a graph in data structure through Adjacency matrix | Data Structure Problems

2019-03-22T15:31:00.000+05:30

Graph is an important part of data structure & algothims,if you keen to learn coding you can't miss graph in data structure,in this article I try to keep the explanation as simple as possible.You know learn programming in coding classes is just boarning.If you want cool stuff you must practice problems.Learn coding through ppractice is the best way.Here also I tell you about graph by examples.
But at first I want to give you a brief intro about our blog;
In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python and other programming languages that may help you land an online job and make your programmers day successfull.We use best data structure notes and best programming resources.
Here goes the article,thanks for having patience & don't forget to share with your friends 👌
Graph is an important part of data structure,it is a collection of some nodes called vertices and some lines called edges.
Graphs are mainly of two types,
i)undirected graph & ii)directed graph.
undirected graph or simple graph is a graph without any direction & directed graph is a graph which have directions,the directions are basically represented by arrows.
But a computer couldn't unnderstand those pictorial representation with nodes,edges,arrows right? So we have to find a way to represent them in way that can be understood by the computer also.
There are two ways to represent a graph they are i)Adjacency Matrix and ii)Adjacency list.
In this article we will talk about Adjacency Matrix only.
Adjacency matrix is a square Matrix used to represent a graph.It consists 0's and 1's. 0 represent no age present between pair of vertices and 1 represent an edge present between pair of vertices.
Lets us take some examples so that you can understand them clearly.Don't worry it will be easy after understanding them you will also enjoy them,trust me. ☺
Here goes the examples:

Adjacency Matrix for a undirected Graph

Adjacency matrix for an directed Graph

Hope this wil help you.In the next article I will tell you about Adjacency List,so stay tuned & please share this article with your friends,I really need your support.

Best websites to learn programming for free onine | A step by step guide that you can't miss

2019-03-21T03:43:00.001+05:30

Programming is the hottest trend now a days and here I provide best websites to learn programming for free online.The list is designed to make you a pro from a complete newbie,also this list is constructed by my point of view & if you disagree or add something new that I missed out please let me know in the comments.
Before starting with the list I want to introduce my website Code Crow to you so that you will be able to know what kind of posts are present in this blog and if you want to be updated when we a put a new post please subscribe to our email list.😀
Intro:In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python and other programming languages that may help you land an online job and make your programmers day successfull.We use best data structure notes and best programming resources.
Here goes the article,dont forget to share with your friends 💗,I divide the list in three segments
Theory->Competitive coding->Placement Preparation
Grabing knowledge(to have a grasp in theory):

1. Geeks for Geeks : This is the best website for begineers that I personally feel.Here you have the access to learn many Computer & programming related subjects (mostly the theory part) in a very lucid way.Here you can also practice competitive prrogramming and prepare yourself for placement and job interview in a very structured manner.

Competitive coding:

1.Hackerrank : After having a brief grasp in theory you can apply your knowledge to hackerrank practise questions.This site also host many coding competitions that will richly develope yiour programming skills.
2.Hackerearth :This is also like hackerrank and it also have many mind blowing coding problems for beginners with a soothing user friendly interface.I must mention that I personally have a soft corner for a hackerearth because it is the first competitive programming platform that I used.
3.Codechef: : The only reason I put Codechef in number three because you must try it after you get familiar with hackerrank & hackerearth beacuse it is slightly tough compare those two. But it is platform worth of to put your time in it,it will make you a complete pro in competitive programming.
4.Topcoder :The most popular competitive coding platform around the globe.It organises high paying coding competiton for developers.You must try it after you spend a sufficient time in competitive programming in other platforms.
5.Codeforces : I personally didn't use it but is also a very popular platform for coding and many of my friends use it.

Placement Preparation:

1.Interviewbit : This is the most recomended platform for placement focused preparetion.You can't go to an interview before checking out this website it has also the mock interview facility.
2. Leetcode : you should check out this also after having a tour through interview bit.

Hope you like this post,feel free to give your suggestions in comment,I will shout out to you 👱
Share with your friends if you find this helpfull and it also motivates me.
Keep follow our blog,in the next post I will post about the best youtube channel for programming,still then bye bye👋

How to create single linked list? | Data structure Problem | coding for beginners

2019-03-17T15:36:00.001+05:30

For coding courses about computer coding for beginners free online in data structures and alogorithms in c,java,python with best programming resources follow our blog

In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python and other programming languages that may help you land an online job and make your programmers day successfull.We use best data structure notes and best programming resources.

Here goes the article,dont forget to share with your friends 😉

#include"stdio.h"
#include"stdlib.h"
struct node
{
int data;
struct node *next;
};
struct node *start; //set the head of the list as global
struct node *createlist(int d)
{
struct node *ptr,*p;
int i;

ptr=(struct node *)malloc(sizeof(struct node)); //allocating memory for the added node
ptr->data=d; //allocate data part
if(start==NULL) //when list is empty
{
ptr->next=start; //set the address part of the node to head which is null
start=ptr; //set the added node as head
}
else
{
p=start;
while(p->next!=NULL)
p=p->next; //traverse the list untill p points to the lat node
p->next=ptr; //link the address part of the last node to new node
ptr->next=NULL; //make the address part of the new node null so that it can become last node
}
return start; //return head
}
void display(struct node *start)
{
struct node *p;
p=start;
while(p!=NULL)
{
printf("%d->",p->data);
p=p->next;
}
}

int main()
{
int n,i,d;
printf("enter the number of nodes\n");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
printf("%dth node value:",i);
scanf("%d",&d);
createlist(d);
}
printf("The list is:");
display(start);
return 0;
}
Here I also attach the output of the program:

feel free to comment for any problem regarding this solution😃😃
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Data Structure:Deleting a node in linked list,Recursive approach in C programming

2019-03-12T01:22:00.000+05:30

Hackerrank problem 5:Data Structure:Deleting a node in linked list,Recursive approach in C programming

In our Programming website about computer coding for free online in data structures and alogorithms in c,java,python etc we try solve progaming,computer coding in easy way with best programming resources.

Here I use recursive approach to solve this;I only wrote the function in this case;the code is as follows:

/ this is solution function

 / Prerequsite:

  Node 

{

      int data;

      Node* link;

  };

Node* deleteNode(Node* root, int pos) {

if(pos==0)

{

return root->link; 

} 

root->link=deleteNode(root->link, pos-1);

return root;

}

/Here pos means position

Data Structure problem in C: Josephus Circle(Taking elements manually) | Competitive coding

2019-03-10T16:02:00.002+05:30

Data Structure problem in C: Josephus Circle(Taking elements manually) | Competitive coding:

In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python

and other programming languages that may help you land an online job and make your programmers day successfull.

We use best data structure notes and best programming resources. Here goes the article,dont forget to share with your friends 😃

Here we take elements manually of values that we want and are inserted in a circle waiting to be executed.counting begins at a specified point in a circle and proceeds around the circle in a specified direction. After a specified number of elements skipped,the next element is executed. The procedure is repeated with the remaining elements,starting with the next element,going in the same direction and skipping the same number of element,untill only one element remains,and is freed.

The code is as follows:

#include"stdio.h"

#include"stdlib.h"

struct node

{

int data;

struct node *next;

}*last=NULL;

struct node *q=NULL;

struct node *insert(int d)

{

struct node* p;

struct node *q;

p=(struct node*)malloc(sizeof(struct node));//allocating memory for the node to be inserted

p->data=d;

if(last==NULL) //when list is empty

{

last=p;

p->next=last;

}

else

{

q=last; //point to the last(next of first)element

while(q->next!=last)

q=q->next; //traversing list

//adding new element

q->next=p;

p->next=last;

}

return last;

}

void display(struct node *last)

{

struct node *q;

q=last;

while(q->next!=last)

{

printf("%d\t",q->data);

q=q->next;

}

printf("%d",q->data);

printf("\n");

}

int main()

{

int d,i,n,h,j;

struct node *p,*q;

printf("enter the number of item\n");

scanf("%d",&n);

for(i=1;i<=n;i++)

{

printf("enter the node value\n");

scanf("%d",&d);

insert(d);

}

display(last);

printf("enter the no of node to be skiped\n");

scanf("%d",&h);

//logic of skip & execute

q=last;

while(q->next!=q)

{

for(j=1;j<h;j++)

{

q=q->next;//points to the h'th node

p=q->next; //point to the h+1'th node,i.e the node to be deleted

}

q->next=p->next;//the desired element is deleted

printf("%d will execute\n",p->data);//print the element which is executed

q=p->next;//now the element after the removed element becomes last and the process goes on

}

printf("\n%d will unchanged",q->data);

}

Data structure Problem | Josephus Circle in Data structure using C |The easiest way you never thought

2019-03-05T22:16:00.003+05:30

Data structure Problem | Josephus Circle in Data structure using C |The easiest way you never thought

In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python

and other programming languages that may help you land an online job and make your programmers day successfull.

We use best data structure notes and best programming resources. Here goes the article,dont forget to share with your friends 😃

Josephus Circle:

people are standing in a circle waiting to be executed.counting begins at a specified point in a circle and proceeds around the circle in a specified direction. After a specified number of people skipped,the next person is executed. The procedure is repeatedwith the remaining people,starting with the next person,going in the same direction and skipping the same number of people,untill only one person remains,and is freed.

The c program to implement this problem is given below:

#include<stdio.h>

#include<stdlib.h>

struct node

{

int data;

struct node *link;

};

void skipexecute(int,struct node *);

struct node *root=NULL,*p=NULL;

main()

{

int count=1,number,m;

struct node *temp;

printf("enter the value of number:\n"); //total number of elements in list

scanf("%d",&number);

printf("enter the value of m:\n"); // we have to remove m+1th element each time

scanf("%d",&m);

while(count<=number)

{

temp=(struct node*)malloc(sizeof(struct node));

temp->data=count++;

if(root==NULL)

{

root=temp;

temp->link=root;

}

else

{

p=root;

while(p->link!=root)

p=p->link;

p->link=temp;

temp->link=root;

}

printf("List in circuler order:\n");

p=root;

while(p->link!=root)

{

printf("%d->",p->data);

p=p->link;

}

printf("%d",p->data);

printf("\n");

skipexecute(m,root);

}

void skipexecute(int m,struct node *front)

{

struct node *flag;

int count1=1;

while(front->link!=front)

{

count1=1;

while(count1!=m+1)

{

flag=front;

front=front->link;

count1++;

}

flag->next=front->link;

printf("%d->",front->data); //nodes which we have to delete

front=flag->link;

}

printf("\n");

printf(" who is freed is:%d\n",front->data);

return;

}

Easy way to solve Data structure | Implementation of circuler Linked list | create list,insert element at at first & display

2019-03-04T09:00:00.000+05:30

Easy way to solve Data structure | Implementation of circuler Linked list | create list,insert element at at first & display:
In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python
and other programming languages that may help you land an online job and make your programmers day successfull.

We use best data structure notes and best programming resources. Here goes the article,dont forget to share with your friends 😃
Circuler Linked list:
Here I include only the functions of creating list,insert an element at first & display the link;the code is as follows:

//Implementation of Circuler linked list
#include<stdio.h>
#include<stdlib.h>
struct node
{
int data;
struct node *link;
};
struct node *last;
void list(int a)
{
struct node *temp,*ptr;
temp=(struct node *)malloc(sizeof(struct node));
temp->data=a;
if(last==NULL)
{
last=temp;
temp->link=last;
}
else
{
temp->link=last->link;
last->link=temp;
last=temp;
}
}
void addbeg(int b)
{
struct node *temp,*ptr;
temp=(struct node *)malloc(sizeof(struct node));
temp->data=b;
if(last==NULL)
{
last=temp;
temp->link=last;
}
else
{
temp->link=last->link;
last->link=temp;
}

}
void display()
{
struct node *ptr;
if(last==NULL)
{
printf("\nList is empty!\n");
return;
}
ptr=last->link;
printf("\nList is:\n");
while(ptr!=last)
{
printf("%d->",ptr->data);
ptr=ptr->link;
}
printf("%d\n",last->data);
}
main()
{
int item,i,ch,n;
while(1)
{
printf("\n1.Create list\n2.Insert at first\n3.Insert at perticuler position\n4.Display\n5.Exit\nEnter your choice\n");
scanf("%d",&ch);
switch(ch)
{
case 1:
printf("Enter number of elements:");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("Enter the element:\n");
scanf("%d",&item);
list(item);
}
break;
case 2:
printf("Enter the element:\n");
scanf("%d",&item);
addbeg(item);
break;
case 4:
display();
break;
case 5:
exit(0);

}
}
}

Data Structure Problem | Stack implementation using Linked list | Best source of competitive coding

2019-03-03T09:00:00.000+05:30

Data Structure Problem | Stack implementation using Linked list | Best source of competitive coding :
In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python
and other programming languages that may help you land an online job and make your programmers day successfull.

We use best data structure notes and best programming resources. Here goes the article,dont forget to share with your friends 😃
Implementing stack using linked:

A stack can be implemented with the help of the linked list & also with the help of the array;here we discuss about the linked list case;more precisely singly linked list;the code is as follows::::

// stack implementation using linked list

#include<stdio.h>

#include<stdlib.h>

struct node

{

int data;

struct node *next;

};

struct node *top=NULL;

void push(int );

void pop();

void display();

main()

{

int ch,item;

while(1)

{

printf("1.Push an element\n2.Pop an element\n3.Display the stack\n4.Exit\nEnter your choice:");

scanf("%d",&ch);

switch(ch)

{

case 1:

printf("Enter the element to be pushed:");

scanf("%d",&item);

push(item);

break;

case 2:

pop();

break;

case 3:

display();

break;

case 4:

exit(0);

}

void push(int a)

{

struct node *temp;

temp=(struct node *)malloc(sizeof(struct node)); //allocating memory for the element to be pushed

temp->data=a;

temp->next=top;

top=temp; //now the pushed elemnt is the top of the stack

}

void pop()

{

struct node *temp;

temp=top;

if(top==NULL)

{

printf("Stack is empty");

}

else

{

temp=top;//temp points to top of stack=>1st element of linked list

printf("Poped element is %d:",temp->data); //1st element(element to be poped) is printed

top=top->next; //now 2nd element of the stack is now the 1st element of stack

free(temp);

}

void display()

{

struct node *temp;

temp=top;

if(top==NULL)

{

printf("stack is empty!");

}

else

{

printf("Elements of stack are:\n");

while(temp!=NULL)

{

printf("%d->",temp->data);

temp=temp->next;

}

printf("\n");

}

Data Structure problem | Inserting a node at a particuler position of a linked list | For Competitive coding Lovers

2019-02-06T22:30:00.001+05:30

Data Structure problem | Inserting a node at a particuler position of a linked list | For Competitive coding Lovers Hacker Rank problem 4:

In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python

and other programming languages that may help you land an online job and make your programmers day successfull.

We use best data structure notes and best programming resources. Here goes the article,dont forget to share with your friends 😃

The code is given below:

/ The function is given below

prerequisite:

node {

    int data;

    node* link;

};

_________________________________________________________________________________

node* position(node* root, int data, int pos) {

struct node  *ptr,*tmp;

int i;

tmp= (node *)malloc(sizeof(node ));

tmp->data=data;

tmp=root;

for(i=0;i<pos-1;i++){

ptr=ptr->link;

if(ptr==NULL)

return ;

}

tmp->link=ptr->link;

ptr->link=tmp;

return root;

}

Data Structure Problem | Insert element at the tail of a linked list | A competive coding lover must check it

2019-02-06T22:30:00.000+05:30

Data Structure Problem | Insert element at the tail of a linked list | A competive coding lover must check it | Hacker Rank problem 2:

In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python

and other programming languages that may help you land an online job and make your programmers day successfull.

We use best data structure notes and best programming resources. Here goes the article,dont forget to share with your friends 😃

node* tail(node* root, int data) {

struct node *t,*p;

p= (struct node *)malloc(sizeof(node));//dynamically allocating memory for the node to be inserted

p->data=data;//allocate the data part of the node to be inserted

p->link=NULL;//because the address part of the last element of linked list is NULL

if(root==NULL){

root=p;

}

else{

t=root;

while(t->link!=NULL){

t=t->link;

}

t->link=p;

}

return root;

}

Data structure Problem | Add element at the the head of a single linked list | competitive coding | HackerRank challenge

2019-02-06T16:00:00.000+05:30

Data structure Problem | Add element at the the head of a single linked list | competitive coding | HackerRank challenge|Hacker Rank problem 3:

In our programming website we teach computer coding to kids and pros for free online in easy way and gives knowledge about Data structure and alogorithm in C,Java,Python

and other programming languages that may help you land an online job and make your programmers day successfull.

We use best data structure notes and best programming resources. Here goes the article,dont forget to share with your friends 😃

node* Head(node* root, int data) {

struct node  *r;

  r = (node *)malloc(sizeof(struct node ));//allocating memory for node to be inserted

  r->data=data;

  r->link=root;

  root=r;

return root;

}

Data Structure problem | Print elements of a single Linked List | Hacker Rank Challenge | Competitive Coding lovers can't miss it

2019-02-05T23:43:00.002+05:30

Data Structure problem | Print elements of a single Linked List | Hacker Rank Challenge | Competitive Coding lovers can't miss it | Hacker Rank Data structure problem 1:

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Here we just discuss about printing the element of a single linked list,this is a solution of a problem given in Hacker Rank.The code is given below:

void print(node* root) {

struct node* t;//this pointer is used to travarse the list

t=root;//set the pointer to head

while(t!=NULL){

printf("%d\t",t->data);//print each elements

t=t->link;//going from one element to another

}

}