#include <iostream>
using namespace std;

struct ListNode {
    int val;
    ListNode *next;
    ListNode() : val(0), next(nullptr) {}
    ListNode(int x) : val(x), next(nullptr) {}
    ListNode(int x, ListNode *next) : val(x), next(next) {}
};
void printList(ListNode* head) {
    while (head) {
        cout << head->val << " ";
        head = head->next;
    }
    cout << endl;
}

class Solution {
public:
    ListNode* reverseBetween(ListNode* head, int left, int right) {
        if (!head || left == right) return head;
        
        ListNode dummy(0);
        dummy.next = head;
        ListNode* prev = &dummy;
        
        for (int i = 0; i < left - 1; i++) {
            prev = prev->next;
        }
        
        ListNode* curr = prev->next;
        ListNode* next = nullptr;
        
        cout << "Initial list before reversing: ";
        printList(dummy.next);
        
        for (int i = 0; i < right - left; i++) {
            next = curr->next;
            curr->next = next->next;
            next->next = prev->next;
            prev->next = next;
            
            cout << "After iteration " << i + 1 << ": ";
            printList(dummy.next);
        }
        
        return dummy.next;
    }
};



int main() {
    ListNode* head = new ListNode(1);
    head->next = new ListNode(2);
    head->next->next = new ListNode(3);
    head->next->next->next = new ListNode(4);
    head->next->next->next->next = new ListNode(5);
    
    int left = 2, right = 4;
    Solution sol;
    head = sol.reverseBetween(head, left, right);
    
    cout << "Final reversed list: ";
    printList(head);
    
    return 0;
}