Homework SourseHow to do insertion sort on a singly linked list with no hea
How to do insertion sort on a singly linked list with no header using C?
Solution
/* C program for insertion sort on a linked list */
#include<stdio.h>
#include<stdlib.h>
/* Link list node */
struct node
{
int data;
struct node* next;
};
// Function to insert a given node in a sorted linked list
void sortedInsert(struct node**, struct node*);
// function to sort a singly linked list using insertion sort
void insertionSort(struct node **head_ref)
{
// Initialize sorted linked list
struct node *sorted = NULL;
// Traverse the given linked list and insert every
// node to sorted
struct node *current = *head_ref;
while (current != NULL)
{
// Store next for next iteration
struct node *next = current->next;
// insert current in sorted linked list
sortedInsert(&sorted, current);
// Update current
current = next;
}
// Update head_ref to point to sorted linked list
*head_ref = sorted;
}
/* function to insert a new_node in a list. Note that this
function expects a pointer to head_ref as this can modify the
head of the input linked list (similar to push())*/
void sortedInsert(struct node** head_ref, struct node* new_node)
{
struct node* current;
/* Special case for the head end */
if (*head_ref == NULL || (*head_ref)->data >= new_node->data)
{
new_node->next = *head_ref;
*head_ref = new_node;
}
else
{
/* Locate the node before the point of insertion */
current = *head_ref;
while (current->next!=NULL &&
current->next->data < new_node->data)
{
current = current->next;
}
new_node->next = current->next;
current->next = new_node;
}
}
/* BELOW FUNCTIONS ARE JUST UTILITY TO TEST sortedInsert */
/* Function to print linked list */
void printList(struct node *head)
{
struct node *temp = head;
while(temp != NULL)
{
printf(\"%d \", temp->data);
temp = temp->next;
}
}
/* A utility function to insert a node at the beginning of linked list */
void push(struct node** head_ref, int new_data)
{
/* allocate node */
struct node* new_node = new node;
/* put in the data */
new_node->data = new_data;
/* link the old list off the new node */
new_node->next = (*head_ref);
/* move the head to point to the new node */
(*head_ref) = new_node;
}
// Driver program to test above functions
int main()
{
struct node *a = NULL;
push(&a, 5);
push(&a, 20);
push(&a, 4);
push(&a, 3);
push(&a, 30);
printf(\"Linked List before sorting \ \");
printList(a);
insertionSort(&a);
printf(\"\ Linked List after sorting \ \");
printList(a);
return 0;
}
| /* C program for insertion sort on a linked list */ #include<stdio.h> #include<stdlib.h> /* Link list node */ struct node { int data; struct node* next; }; // Function to insert a given node in a sorted linked list void sortedInsert(struct node**, struct node*); // function to sort a singly linked list using insertion sort void insertionSort(struct node **head_ref) { // Initialize sorted linked list struct node *sorted = NULL; // Traverse the given linked list and insert every // node to sorted struct node *current = *head_ref; while (current != NULL) { // Store next for next iteration struct node *next = current->next; // insert current in sorted linked list sortedInsert(&sorted, current); // Update current current = next; } // Update head_ref to point to sorted linked list *head_ref = sorted; } /* function to insert a new_node in a list. Note that this function expects a pointer to head_ref as this can modify the head of the input linked list (similar to push())*/ void sortedInsert(struct node** head_ref, struct node* new_node) { struct node* current; /* Special case for the head end */ if (*head_ref == NULL || (*head_ref)->data >= new_node->data) { new_node->next = *head_ref; *head_ref = new_node; } else { /* Locate the node before the point of insertion */ current = *head_ref; while (current->next!=NULL && current->next->data < new_node->data) { current = current->next; } new_node->next = current->next; current->next = new_node; } } /* BELOW FUNCTIONS ARE JUST UTILITY TO TEST sortedInsert */ /* Function to print linked list */ void printList(struct node *head) { struct node *temp = head; while(temp != NULL) { printf(\"%d \", temp->data); temp = temp->next; } } /* A utility function to insert a node at the beginning of linked list */ void push(struct node** head_ref, int new_data) { /* allocate node */ struct node* new_node = new node; /* put in the data */ new_node->data = new_data; /* link the old list off the new node */ new_node->next = (*head_ref); /* move the head to point to the new node */ (*head_ref) = new_node; } // Driver program to test above functions int main() { struct node *a = NULL; push(&a, 5); push(&a, 20); push(&a, 4); push(&a, 3); push(&a, 30); printf(\"Linked List before sorting \ \"); printList(a); insertionSort(&a); printf(\"\ Linked List after sorting \ \"); printList(a); return 0; } |
