学步园

//Reverse linklist in block
//eg. block size is 3 and list is
//1 2 3 4 5 6 7 8
//Output: 3 2 1 6 5 4 8 7

LNK_NODE*  ReverseByBlock(LNK_NODE* pHead ,int nBlockSize)

#include <iostream>

using namespace std;

//1 2 3 4 5 6 7 8

struct Node {
    int data;
    Node *next;
};

Node *genLink() {
    Node head;
    Node *pt = &head;
    for (int i = 1; i < 9 ; ++i) {
        pt->next = new Node;
        pt->next->data = i;
        pt->next->next = NULL;
        pt = pt->next;
    }

    return head.next;
}

void rmLink(Node *head) {
    while(head) {
        Node *t = head;
        head = head->next;
        delete t;
    }
}

void print(Node *head) {
    while (head) {
        cout<<head->data<<" ";
        head = head->next;
    }
}

Node *reverseByBlock(Node *head, int n) {
    if (n <= 1)
        return head;
    
    Node root;
    Node *tail = &root;

    
    Node *fir = head;


    while (fir) {
        Node *sec = NULL;
        int i = 0;
        Node *nextTail = fir;
        while (fir && i <n) {
            Node *t = fir;
            fir = fir->next;
            t->next = sec;
            sec = t;
            ++i;
        }

        tail->next = sec;
        tail = nextTail;
    }

    return root.next;
}

int main() {
    Node *head = genLink();
    print(head);

    cout<<endl;
    Node *rh = reverseByBlock(head,1);
    print(rh);
    rmLink(rh);
}