Deleting every Nth node from a Circular Linked list - Interview Question

Deleting every Nth node from a linked lint - Implementaion Using C - Interview Question

                             Scenario

Consider  a game in which players are arranged circularly. The

game has to be played in a way demonstrared as follows.

1.) The games starts from first player as current player.

2.)A random number(n) from 1 to 10 is generated.

3.)  *The count goes from the current player and deletes the             

         Nth player…

      *After deleting the player, now the game starts from the player

         next to the  deleted player…

      *The game is to be stopped if there is only one player and the 

        player is  declared as a winner…

      (Design an algorithm for the game)

 #include<stdio.h>
#include<stdlib.h>
typedef struct Node
 {
    int data;
    struct Node *prev;
    struct Node *next;
 }Node;
Node *start=NULL;

void insert(Node *temp)
{
    Node *var,*last;
    Node *ptr=start;
  
    if(start==NULL)
    {
        temp->next=temp;
        temp->prev=temp;
        start=temp;
    }
    else
    {
      while(ptr->next!=start)
        {  
            ptr=ptr->next;
        }
         last=start->prev;
         ptr->next=temp;
         temp->prev=last;
         last->next=temp;
         temp->next=start;
         start->prev=temp;
    }
}

void display(Node *start)
{
  
    Node *ptr=start;
    if(start==NULL)
    printf("\n No elements present");
    else
    {
         printf("\n Elements in the Linked List are:");
        while(ptr->next!=start)
        {  
            printf("\n%d",ptr->data);      
            ptr=ptr->next;
        }
            printf("\n%d",ptr->data);  
    }
return;
}

int delete1(Node *start,int n)
{
    Node *t=start,*p,*q;
    int count;
    while(t->next!=t->next->next)  
    {       
        count=1;
        while(count<n)
        {  
            t=t->next;
            count++;
        }
        p=t->prev; q=t->next;
        p->next=q; q->prev=p;  
        free(t);
      
        t=q;  
    }
    return t->data;
}

Node *createNode(int data)
{
    Node *temp=(struct Node*)malloc(sizeof(struct Node));
    temp->data=data;
    return temp;  
}
int main()
{
    int data;
    Node *temp;

    temp=createNode(10);
    insert(temp);
      
    temp=createNode(20);
    insert(temp);  
  
    temp=createNode(30);
    insert(temp);  
  
    temp=createNode(40);
    insert(temp);  
  
    temp=createNode(50);
    insert(temp);  
  
    display(start);
  
    data=delete1(start,4);     /*Winner */
    printf("\n Winner is :: %d",data);  
    return 0;
}

 

 

O/P:  when N=4

 

 

 

FLAMES - Finding realtionship between You both Using C

//flames using C
#include<stdio.h>
int main()
{
char name1[25],name2[25];
register int i,j;
static int count_fname,count_lname;
int sum=0;
char temp;
printf("\n Enter your name::");
scanf("%s",name1);
printf("\nEnter Miss/Mr 'X' Name::");
scanf("%s",name2);
i=0,j=0;

while(name1[i]!='\0')  /*Sorting the first name*/
{
j=i+1;
while(name1[j]!='\0')
{
if(name1[i]>name1[j])
{
temp=name1[i];
name1[i]=name1[j];
name1[j]=temp;
}

j++;
   }
 
i++;
count_fname=i;
}
printf("\n%s",name1);


i=0,j=0;
while(name2[i]!='\0')          /*Sorting the second name*/
{
j=i+1;
while(name2[j]!='\0')
{
if(name2[i]>name2[j])
{
temp=name2[i];
name2[i]=name2[j];
name2[j]=temp;
}

j++;
   }
 
i++;
count_lname=i;
}

printf("\n%s",name2);



i=0,j=0;
while(name1[i]!='\0' && name2[j]!='\0')     /*Compare to get perfect count*/
{
if(name1[i]<name2[j])
{
i++;
}
else if(name1[i]>name2[j])
{
j++;
}
else if(name1[i]==name2[j])
{

count_fname=count_fname-1;
count_lname=count_lname-1;


i++;
j++;
}
}
printf("\n Value of count_fname:%d",count_fname);
printf("\n Value of count_fname:%d",count_lname);
sum=(count_fname+count_lname);  //sum up remaining letters in two names*/
//sum=sum%6;
switch(sum)
{
case 0:
printf("\n Sorry Same Name found!!! else alike palindrome or anagram");
break;
case 1:
printf("\n -->Sister-->");
break;

case 2:
printf("\n -->Enemy-->");
break;
case 3:
printf("\n -->Friends-->");
break;

case 4:
printf("\n -->Enemy-->");
break;

case 5:
printf("\n -->Friends-->");
break;

case 6:
printf("\n -->You Gonna MARRY each other-->");
break;

case 7:
printf("\n -->Enemy-->");
break;

case 8:
printf("\n -->Affection-->");
break;

case 9:
printf("\n -->Enemy-->");
break;

case 10:
printf("\n Love");

case 11:
printf("\n  You Gonna MARRY each other");
break;

case 12:
printf("\n Affection");
break;

case 13:
printf("\n Affection");
break;

case 14:
printf("\n Friends");
break;
case 15:
printf("\n You gonna marry each other");
break;

case 16:
printf("\n Friends");
break;



}


return 0;
}

Writing an Array of structures into a file & Reading a file into an Array of structures in c

                      Student Mark List Preparation

#include<stdio.h>

FILE *fp;
struct stud
{
    int sid;
    int sm[5];
    int tot;
    float avg;
    int cls;
    char pf;
};
void cal(struct stud s[],int);
void print(struct stud s[],int);
int main()
{

    struct stud s[10];
    int i,j,n;

    printf("Enter the no.of students:");
    scanf("%d",&n);

       //s=(struct stud*)malloc(sizeof(struct stud)*n);
    for(i=0;i<n;i++)
    {
        printf("Enter the student id:");
        scanf("%d",&s[i].sid);
        printf("enter 5 marks:");
        for(j=0;j<5;j++)
        scanf("%d",&s[i].sm[j]);
    }
        cal(s,n);
return 0;
}
void cal(struct stud s[],int n)
{
    int i;
    for(i=0;i<n;i++)
    {
        if(s[i].sm[0]>50 && s[i].sm[1]>50 && s[i].sm[2]>50 && s[i].sm[3]>50 && s[i].sm[4]>50)
            s[i].pf='p';
        else
            s[i].pf='f';
        if(s[i].pf=='p')
        {
            s[i].tot=(s[i].sm[0]+s[i].sm[1]+s[i].sm[2]+s[i].sm[3]+s[i].sm[4]);
            s[i].avg=(s[i].tot)/5;
            if(s[i].avg>70)
                s[i].cls=1;
            else if(s[i].avg>60 && s[i].avg<70)
                s[i].cls=2;
            else //(s[i].avg>50 && s[i].avg<60)
                s[i].cls=3;


        }
        else
        {
            printf("FAIL");
        }
    }
            print(s,n);


   
    return;
}
void print(struct stud s[],int n)
{
    int i,j;
fp =fopen("marklist.txt","w+");

    for(i=0;i<n;i++)
    {
      
        fprintf(fp,"%d    ",s[i].sid);
        for(j=0;j<5;j++)
        {
        fprintf(fp,"%d    ",s[i].sm[j]);
        }
        fprintf(fp,"%d    ",s[i].tot);
        fprintf(fp,"%f    ",s[i].avg);
        fprintf(fp,"%d    ",s[i].cls);

       fprintf(fp,"\n");
    }
    fclose(fp);
   
   
   
fp=fopen("marklist.txt","r");
printf("SID   C   COA   DS   RDBMS    JAVA   TOTAL   AVG    CLASS \n");
for(i=1;i<=n;i++)
{
    j=0;
   
fscanf(fp,"%d  %d %d %d %d %d %d %f %d",&s[i].sid,&s[i].sm[j],&s[i].sm[j+1],&s[i].sm[j+2],&s[i].sm[j+3],&s[i].sm[j+4],&s[i].tot,&s[i].avg,&s[i].cls);

printf("%d %d %d %d %d %d %d %f %d\n",s[i].sid,s[i].sm[j],s[i].sm[j+1],s[i].sm[j+2],s[i].sm[j+3],s[i].sm[4],s[i].tot,s[i].avg,s[i].cls);

}
fclose(fp);
    return;
}