Solved Sorting Linked List in C++ (#281)

C++/Sorting-Linked-List.cpp

@@ -0,0 +1,101 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node {
+    int data;
+    struct Node * next;
+
+    Node(int x, Node* n = NULL) {
+        data = x;
+        next = n;
+    }
+};
+
+Node* convertArrayIntoLinkedList(vector<int> &arr) {
+    Node* head = new Node(arr[0]);
+    Node* mover = head;
+
+    for(int i = 1; i < arr.size(); i++) {
+        Node* temp = new Node(arr[i]);
+        mover->next = temp;
+        mover = temp;
+    }
+
+    return head;
+}
+
+void print(Node* head) {
+    Node* temp = head;
+    while(temp != nullptr) {
+        cout << temp->data << " ";
+        temp = temp->next;
+    }
+    cout << endl;
+}
+
+Node* mergeTwoSortedLinkedLists(Node* list1, Node* list2) {
+    Node* dummyNode = new Node(-1);
+    Node* temp = dummyNode;
+
+    while (list1 != nullptr && list2 != nullptr) {
+        if (list1->data <= list2->data) {
+            temp->next = list1;
+            list1 = list1->next;
+        } else {
+            temp->next = list2;
+            list2 = list2->next;
+        }
+        temp = temp->next; 
+    }
+
+    if (list1 != nullptr) {
+        temp->next = list1;
+    } else {
+        temp->next = list2;
+    }
+
+    return dummyNode->next;
+}
+
+Node* findMiddle(Node* head){
+    if (head == nullptr || head->next == nullptr) {
+        return head;
+    }
+
+    Node* slow = head;
+    Node* fast = head->next;
+
+    while (fast != nullptr && fast->next != nullptr) {
+        slow = slow->next;
+        fast = fast->next->next;
+    }
+
+    return slow;
+}
+
+Node* sortLinkedList(Node* head) {
+    if(head == nullptr || head->next == nullptr) {
+        return head;
+    }
+
+    Node* middle = findMiddle(head);
+
+    Node* right = middle->next;
+    middle->next = nullptr;
+    Node* left = head;
+
+    left = sortLinkedList(left);
+    right = sortLinkedList(right);
+
+    return mergeTwoSortedLinkedLists(left, right);
+}
+
+int main() {
+    vector<int> arr = {12, 5, 8, 7, 10, 51, 21, 31};
+    Node* head = convertArrayIntoLinkedList(arr);
+
+    head = sortLinkedList(head);
+    print(head);
+
+    return 0;
+}