链表逆序（递归法）

来自SO，貌似没啥实际应用，但是思路不错，留存。

#include <Windows.h>
#include <iostream>
using namespace std;

struct node
{
    int data;
    node* next;
    node(int d, node* p):data(d), next(p){}
};

void print_list(node* head)
{
    node* temp = head;
    while(temp != NULL)
    {
        cout << temp->data << " -> ";
        temp = temp->next;
    }
    cout << "NULL";
    cout << endl;
}

void reverse_linklist1(node*& head)
{
    node* first = head; 
    node* rest  = first->next;

    if (rest == NULL)
       return;  

    reverse_linklist1(rest);

    first->next->next  = first; 
    first->next  = NULL;         

    head = rest;             
}

void reverse_linklist2(struct node*& head)
{
    node *p = head;
    if(p->next == NULL){
        return;
    }

    head = p->next;
    reverse_linklist2(head);

    p->next->next = p;
    p->next = NULL;
}

int main(void)
{
    // build link list
    node* p3 = new node(3, NULL);
    node* p2 = new node(2, p3);
    node* p1 = new node(1, p2);

    print_list(p1);
    reverse_linklist2(p1);
    print_list(p1);

    getchar();
    return 0;
}

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