merge sort linked list

#include<iostream>

using namespace std;

struct node
{
    int x;
    node* next;
};

void Print(node* r){
    while (r != NULL){
        cout << r->x << ", ";
        r = r->next;
    }cout << endl;
}

void Swap(node* a, node* b){
    int t = a->x;
    a->x = b->x;
    b->x = t;
}

node* Sort(node* r, int n){ //return the first node

    if (n == 1)
        return r;

    else if (n == 2){
        if (r->x > r->next->x)
            Swap(r, r->next);
        return r;
    }

    bool s1 = true, s2 = true;
    int i = 0;
    node *tr = r, *f, *p;
    while (i<(n-1)/2){
        if (tr->x > tr->next->x)
            s1 = false;
        tr = tr->next;
        i++;
    }
    tr = tr->next;
    i++;
    int ti = i;
    node* r2 = tr;
    while (ti<n-1){
        if (tr->x > tr->next->x){
            s2 = false;
            break;
        }
        tr = tr->next;
        ti++;
    }
    if (!s1)
        r=Sort(r, i);
    if (!s2)
        r2=Sort(r2, n - i);

    node* first = r;
    f = r;

    int ki = 0;
    tr = r;
    while (ki<(n - 1) / 2){
        tr = tr->next;
        ki++;
    }
    p = tr;

    ti = i;
    int k = 0;
    while (i < n && k<ti){
        if (r->x > r2->x){
            p->next = r2->next;
            r2->next = r;
            if (f != r){
                f->next = r2;
                f = f->next;
            }
            else{
                first = r2;
                f = r2;
            }
            r2 = p->next;
            i++;
        }
        else{
            if (r != f)
                f = f->next;
            r = r->next;
            k++;
        }
    }
    return first;
}


int main(){

    node* r = new node;

    node* tr = r;
    node* pr = r;
    int n = 10,i=0;
    while (i < n){
        tr->x = rand()%100000;
        tr->next = new node;
        pr = tr;
        tr = tr->next;
        i++;
    }
    delete tr;
    pr->next = NULL;

    Print(r);
    cout << "start\n";
    r = Sort(r, n);
    cout << "end\n";
    Print(r);

    while (r != NULL){
        node* tmp = r;
        r = r->next;
        delete tmp;
    }

    getchar();
    return 0;
}