Linked List Sorting (链表)

Linked List Sorting (链表)

 

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 (< 105) 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 [-105, 105], 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

坑点：1、可能是空链表  2、并不是每个节点都在链表上的

#include <iostream>

#include <vector>

#include<iomanip>

#include <algorithm>

using namespace std;

struct node

{

  int add;

  int data;

  int next;

};

node a[100000],b[100000];

bool cmp(node n1,node n2)

{

   return n1.data<n2.data;

}

int main()

{

      int len,fir,add,data,next;

      int i;

      while(cin>>len)

      {

            cin>>fir;

            for(i=0;i<len;i++)

            {

               cin>>add>>data>>next;

               node n;

               n.add=add;

               n.data=data;

               n.next=next;

               a[add]=n;

            }

            if(fir==-1)

            {

              cout<<"0 -1"<<endl;

              continue;

            }

        i=0;

            while(fir!=-1)

            {

               b[i].add =a[fir].add;

               b[i].data =a[fir].data;

               b[i].next =a[fir].next;

               fir = a[fir].next;

               ++i;

            }

          int len=i;

         sort(b,b+len,cmp);

            for(i=0;i<len-1;i++)

            {

                b[i].next=b[i+1].add;

            }

            b[len-1].next=-1;

            cout<<len<<" "<<setfill('0')<<setw(5)<<b[0].add<<endl;

            for(i=0;i<len;i++)

            {

                 if(b[i].next==-1)

                        cout<<setfill('0')<<setw(5)<<b[i].add<<" "<<b[i].data<<" "<<-1<<endl;

                  else

                        cout<<setfill('0')<<setw(5)<<b[i].add<<" "<<b[i].data<<" "<<setfill('0')<<setw(5)<<b[i].next<<endl;

            }

      }

  return 0;

}