From e625e7963180d7eaf4fa742dd403e2b668c6fd12 Mon Sep 17 00:00:00 2001
From: Siva Prasad A <164894350+SivaPA08@users.noreply.github.com>
Date: Wed, 26 Feb 2025 21:27:19 +0530
Subject: [PATCH] Create sort_linked_list.cpp

---
 sorting/sort_linked_list.cpp | 81 ++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 sorting/sort_linked_list.cpp

diff --git a/sorting/sort_linked_list.cpp b/sorting/sort_linked_list.cpp
new file mode 100644
index 0000000000..1d3dd27717
--- /dev/null
+++ b/sorting/sort_linked_list.cpp
@@ -0,0 +1,81 @@
+//C++ program for sorting a linked list
+#include <iostream>
+using namespace std;
+// Definition of the ListNode structure
+// Represents a node in the linked list
+struct ListNode {
+    int val;         // Value of the node
+    ListNode* next;  // Pointer to the next node
+    ListNode() : val(0), next(nullptr) {}
+    ListNode(int x) : val(x), next(nullptr) {}
+    ListNode(int x, ListNode* next) : val(x), next(next) {}
+};
+
+// Function to find the middle node of the linked list using slow and fast
+// pointers
+ListNode* mid(ListNode* h) {
+    ListNode *s = h, *f = h->next; //Here 's' is the slow pointer and 'f' is the fast pointer
+    while (f && f->next) {
+        s = s->next;
+        f = f->next->next;
+    }
+    return s;
+}
+
+// Function to merge two sorted linked lists
+ListNode* mg(ListNode* l, ListNode* r) {
+    if (l == nullptr)
+        return r;  // If left list is empty, return right list
+    if (r == nullptr)
+        return l;           // If right list is empty, return left list
+    if (l->val < r->val) {  // Compare values and recursively merge
+        l->next = mg(l->next, r);
+        return l;
+    } else {
+        r->next = mg(l, r->next);
+        return r;
+    }
+}
+
+// Function to sort the linked list using merge sort
+ListNode* sortList(ListNode* h) {
+    if (h == nullptr || h->next == nullptr)
+        return h;          // Base case: list is empty or has one node
+    ListNode* m = mid(h);  // Find the middle node
+    ListNode *l = h, *r = m->next;
+    m->next = nullptr;  // Split the list into two halves
+    l = sortList(l);    // Recursively sort the left half
+    r = sortList(r);    // Recursively sort the right half
+    return mg(l, r);    // Merge the two sorted halves
+}
+
+// Function to push a new node with a given value to the front of the list
+void push(ListNode** h, int new_val) {
+    ListNode* new_node = new ListNode(new_val);
+    new_node->next = *h;
+    *h = new_node;
+}
+
+int main() {
+    ListNode* head = nullptr;
+
+    // Push elements into the list
+    push(&head, 1);
+    push(&head, 10);
+    push(&head, -8);
+    push(&head, 3);
+    push(&head, 7);
+
+    // Sort the list using merge sort
+    head = sortList(head);
+
+    // Print the sorted list
+    ListNode* temp = head;
+    while (temp) {
+        cout << temp->val << " ";  // Print the value of each node
+        temp = temp->next;         // Move to the next node
+    }
+    cout << endl;
+
+    return 0;
+}