1 min read
https://practice.geeksforgeeks.org/problems/reverse-a-linked-list-in-groups-of-given-size/1
class Solution {
public:
struct node *reverse(struct node *head, int k) {
stack<node *> st;
struct node *curr = head;
struct node *prev = nullptr;
while (curr != nullptr) {
int ctr = 0;
while (curr != nullptr && ctr < k) {
st.push(curr);
curr = curr->next;
ctr++;
}
while (!st.empty()) {
if (prev == nullptr) {
prev = st.top();
head = prev;
st.pop();
} else {
prev->next = st.top();
prev = prev->next;
st.pop();
}
}
}
prev->next = nullptr;
return head;
}
};