C++单链表反转、两有序链表合并仍有序

  1 #include<iostream>
  2
  3 struct Node
  4 {
  5     int data;
  6     Node *next;
  7 };
  8
  9 typedef struct Node Node;
 10
 11 Node *Reverse(Node *head)
 12 {
 13     if (NULL == head || NULL == head->next)
 14         return head;
 15     Node *p1 = head;
 16     Node *p2 = p1->next;
 17     Node *p3 = p2->next;
 18     p1->next = NULL;
 19     while (p3 != NULL)
 20     {
 21         p2->next = p1;
 22         p1 = p2;
 23         p2 = p3;
 24         p3 = p3->next;
 25     }
 26
 27     p2->next = p1;
 28     head = p2;
 29     return head;
 30 }
 31
 32 // 循环算法
 33 Node *Merge(Node *head1, Node *head2)
 34 {
 35     if (NULL == head1)
 36         return head2;
 37     if (NULL == head2)
 38         return head1;
 39     Node *head = NULL;
 40     Node *p1 = NULL;
 41     Node *p2 = NULL;
 42     if (head1->data < head2->data)
 43     {
 44         head = head1;
 45         p1 = head1->next;
 46         p2 = head2;
 47     }
 48     else
 49     {
 50         head = head2;
 51         p2 = head2->next;
 52         p2 = head1;
 53     }
 54
 55     Node *cur = head;
 56     while (NULL!=p1 && NULL!=p2)
 57     {
 58         if (p1->data < p2->data)
 59         {
 60             cur->next = p1;
 61             cur = p1;
 62             p1 = p1->next;
 63         }
 64         else
 65         {
 66             cur->next = p2;
 67             cur = p2;
 68             p2 = p2->next;
 69         }
 70     }
 71     if (NULL == p1)
 72         cur->next = p2;
 73     if (NULL == p2)
 74         cur->next = p1;
 75
 76     return head;
 77 }
 78
 79 // 递归算法
 80 Node *MergeRecursive(Node *head1, Node *head2)
 81 {
 82     if (NULL == head1)
 83         return head2;
 84     if (NULL == head2)
 85         return head1;
 86     Node *head = NULL;
 87
 88     if (head1->data < head2->data)
 89     {
 90         head = head1;
 91         head->next = MergeRecursive(head1->next, head2);
 92     }
 93     else
 94     {
 95         head = head2;
 96         head->next = MergeRecursive(head1, head2->next);
 97     }
 98
 99     return head;
100 }
101
102 int main(void)
103 {
104     return 0;
105 }