Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Insert into a Sorted Circular Linked List in C++
Suppose we have a node from a Circular Linked List which is sorted in increasing order, we have to define a function to insert a value insertVal into the list such that it remains a sorted circular list.
The node can be a reference to any single node in the list, and may not be necessarily the first value of the circular list. If there are multiple suitable places for insertion, we can choose any place to insert the new value. If the list is empty, then we have to create a new single circular list and return the reference to that single node. Otherwise, we should return the original given node.
So, if the input is like head = [3,4,1], insertVal = 2, image, then the output will be [3,4,1,2], image
To solve this, we will follow these steps −
if head is null, then −
head := new node with val
next of head := head
Otherwise
curr = next of head
prev = head
temp = new node with val
done := false
Do infinite looping, do −
if val in curr >= val and val of prev <= val, then −
prev := next of temp
temp := next of curr
done := true
Come out from the loop
if val of prev > val of curr, then −
if val of prev <= val or val <= val of curr, then −
prev := next of temp
temp := next of curr
done := true
Come out from the loop
if curr is same as head, then −
Come out from the loop
prev := curr
curr := next of curr
if done is false, then −
temp := next of head
prev := next of temp
head := temp
return head
Example
Let us see the following implementation to get a better understanding −
#include <bits/stdc++.h>
using namespace std;
class Node {
public:
int val;
Node* next;
Node() {}
Node(int _val) {
val = _val;
next = NULL;
}
Node(int _val, Node* _next) {
val = _val;
next = _next;
}
};
class Solution {
public:
Node* insert(Node* head, int val) {
if(!head){
head = new Node(val);
head->next = head;
}
else{
Node* curr = head->next;
Node* prev = head;
Node* temp = new Node(val);
bool done = false;
while(1){
if (curr->val >= val && prev->val <= val) {
prev->next = temp;
temp->next = curr;
done = true;
break;
}
if (prev->val > curr->val) {
if (prev->val <= val || val <= curr->val) {
prev->next = temp;
temp->next = curr;
done = true;
break;
}
}
if (curr == head)
break;
prev = curr;
curr = curr->next;
}
if(!done){
temp->next = head;
prev->next = temp;
head = temp;
}
}
return head;
}
};
main(){
Solution ob;
Node *head = new Node(3);
head->next = new Node(4);
head->next->next = new Node(1, head);
ob.insert(head, 2);
Node *temp = head;
if (head != NULL){
do{
cout << temp->val << " ";
temp = temp->next;
}
while (temp != head);
}
}Input
node *head = new Node(3); head->next = new Node(4); head->next->next = new Node(1, head); insertVal = 2
Output
3 4 1 2
297 Views
