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Insertion_in_circular.cpp
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Insertion_in_circular.cpp
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#include <bits/stdc++.h>
using namespace std;
class Node
{
public:
int data;
Node *next;
} * head;
void create(int a[], int n)
{
Node *t, *last;
head = new Node;
head->data = a[0];
head->next = head;
last = head;
for (int i = 1; i < n; i++)
{
t = new Node;
t->data = a[i];
t->next = last->next;
last->next = t;
last = t;
}
}
// to find the length of a list..
int Length()
{
Node *p = head;
int count = 0;
do
{
count++;
p = p->next;
} while (p != head);
return count;
}
// insertion in circular LL------------>
void insertion(int pos, int x)
{
Node *p = head, *t;
t = new Node;
// check that if given pos is valid or not..
if (pos < 0 || pos > Length())
return;
if (pos == 0) // either insert before head or after last node -- it is same in circular list.
{
if (head == 0) // if one node is there..
{
head = t;
head->next = head;
}
else
{
while (p->next != head)
{
p = p->next;
}
t->data = x;
t->next = head;
p->next = t;
head = t;
}
}
else
{
for (int i = 0; i < pos - 1 and p; i++)
{
p = p->next;
}
t->data = x;
t->next = p->next;
p->next = t;
}
}
void display(Node *p)
{
do
{
cout << p->data << " ";
p = p->next;
} while (p != head);
cout << endl;
}
int main()
{
int n;
cin >> n;
int a[n];
for (int i = 0; i < n; i++)
{
cin >> a[i];
}
create(a, n);
// insertion in circular LL------------>
int pos, x;
cin >> pos >> x;
insertion(pos, x);
display(head);
// cout << Length();
}