PAT 甲级A1052 Linked List Sorting （25 分）

题目： 

1052 Linked List Sorting （25 分）

A linked list consists of a series of structures, which are not necessarily adjacent in memory. We assume that each structure contains an integer key and a Next pointer to the next structure. Now given a linked list, you are supposed to sort the structures according to their key values in increasing order.

Input Specification:

Each input file contains one test case. For each case, the first line contains a positive N (<10​5​​) and an address of the head node, where N is the total number of nodes in memory and the address of a node is a 5-digit positive integer. NULL is represented by −1.

Then N lines follow, each describes a node in the format:

Address Key Next

where Address is the address of the node in memory, Key is an integer in [−10​5​​,10​5​​], and Next is the address of the next node. It is guaranteed that all the keys are distinct and there is no cycle in the linked list starting from the head node.

Output Specification:

For each test case, the output format is the same as that of the input, where N is the total number of nodes in the list and all the nodes must be sorted order.

Sample Input:

5 00001
11111 100 -1
00001 0 22222
33333 100000 11111
12345 -1 33333
22222 1000 12345

Sample Output:

5 12345
12345 -1 00001
00001 0 11111
11111 100 22222
22222 1000 33333
33333 100000 -1

题意：

   要给链表按照值的递增排序。给出若干条静态链表的结点，格式如下当前地址，结点值，下一个结点地址。第一行会给出输入的行数以及查询的首地址。输出时第一行输出 该链表的节点数和新的首地址，接着便输出链表，一行一个节点。

思路：

  1、用两个静态链表解决，同时设置初始的结点值为inf（为了特判没有所查询的链表）。第一个链表用下标来存储地址，第二个用于存储有效的链表。

  2、用sort函数按照值从小到大排序（题目已经说了值都是不相同的）。

#include
#include
using namespace std;
const int inf=0x7FFFFFFF;//不一定要设置成最大值，只要比有效值大就行
const int maxn=1000100;
struct Node{
	int address;
	int key;
	int next;
	Node(){
		key=inf;
	}
}node[maxn],ans[maxn];

bool cmp(Node a,Node b){
	return a.key