I solved this problem for my academic course COMPUTER PROGRAMMING. Here I used two pointer namely p,q for traversing the linked list. And a temporary pointer to store data of q while traversing. First of all, for corner cases viz. zero and one element return dirctltly head. Then I store the data of head to p and put NULL to the next of head(head->next), Same procedure I follow while traversing firstly I store the data q moves one element faster than p, while traversing firstly I store the data of q in store pointer and move q one forwards then connect the current pointer to the previous pinter and so on Up to q becomes NULL.
This is my CPP solution.
class Solution {
public:
ListNode* reverseList(ListNode* head) {
if(head==NULL || head->next==NULL){
return head;
}
ListNode *p = head ,*q = head->next;
head->next = NULL;
while(q!=NULL){
ListNode *store = q;
q = q->next;
store->next = p;
p = store;
}
return p;
}
};