PAT 乙级 1025. 反转链表 (25)(没做出来)

时间:2022-03-03 15:57:02

给定一个常数K以及一个单链表L,请编写程序将L中每K个结点反转。例如:给定L为1→2→3→4→5→6,K为3,则输出应该为3→2→1→6→5→4;如果K为4,则输出应该为4→3→2→1→5→6,即最后不到K个元素不反转。

输入格式:

每个输入包含1个测试用例。每个测试用例第1行给出第1个结点的地址、结点总个数正整数N(<= 105)、以及正整数K(<=N),即要求反转的子链结点的个数。结点的地址是5位非负整数,NULL地址用-1表示。

接下来有N行,每行格式为:

Address Data Next

其中Address是结点地址,Data是该结点保存的整数数据,Next是下一结点的地址。

输出格式:

对每个测试用例,顺序输出反转后的链表,其上每个结点占一行,格式与输入相同。

输入样例:
00100 6 4
00000 4 99999
00100 1 12309
68237 6 -1
33218 3 00000
99999 5 68237
12309 2 33218
输出样例:
00000 4 33218
33218 3 12309
12309 2 00100
00100 1 99999
99999 5 68237
68237 6 -1
分析:
这道题目···到最后也没做出来。一是注意超时的问题····二是有些节点是没有用的····有一个测试点始终过不了,真是蛋疼~以后再说吧~
using System;
using System.Collections.Generic;

namespace PAT
{
    class Program
    {
        public static Node[] nodes = new Node[100000];

        static void Main(string[] args)
        {
            string[] infos = Console.ReadLine().Split(' ');
            int beginAddress = int.Parse(infos[0]);
            int length = int.Parse(infos[1]);
            int unit = int.Parse(infos[2]);
            int count = 0;  //有些节点是废节点

            GetNodes(length);

            List<Node> sortedNodes = new List<Node>(length);
            int currentAddress = beginAddress;
            if (!nodes[currentAddress].used)
                Console.Write("-1");
            else
            {
                do
                {
                    sortedNodes.Add(nodes[currentAddress]);
                    currentAddress = nodes[currentAddress].next;
                    count++;
                }
                while (currentAddress != -1);

                List<Node> areaNodes = new List<Node>(unit);
                int nextAddress;

                for (int i = 0; i < count; i++)
                {
                    if (i != 0 && i % unit == 0)
                    {
                        nextAddress = sortedNodes[i].address;
                        SortArea(areaNodes, unit, nextAddress);
                        areaNodes = new List<Node>(unit);
                    }
                    areaNodes.Add(sortedNodes[i]);
                }

                if (areaNodes.Count == unit)
                    SortArea(areaNodes, unit, -1);

                else if (areaNodes.Count != 0)
                {
                    int index;
                    for (index = 0; index < areaNodes.Count - 1; index++)
                    {
                        Console.WriteLine("{0:00000} {1:00000} {2:00000}", areaNodes[index].address, areaNodes[index].value, areaNodes[index + 1].address);

                    }
                    Console.WriteLine("{0:00000} {1:00000} {2}", areaNodes[index].address, areaNodes[index].value, "-1");
                }
            }
        }

        static void GetNodes(int length)
        {
            string[] infos;
            int address;
            for (int i = 0; i < length; i++)
            {
                infos = Console.ReadLine().Split(' ');
                address = int.Parse(infos[0]);
                nodes[address].address = address;
                nodes[address].value = infos[1];
                nodes[address].next = int.Parse(infos[2]);
                nodes[address].used = true;
            }
        }

        static void SortArea(List<Node> areaNodes, int areaLength, int nextAreaAddress)
        {
            int i;
            for (i = 0; i < areaLength - 1; i++)
            {
                Console.WriteLine("{0:00000} {1:00000} {2:00000}", areaNodes[areaLength - i - 1].address, areaNodes[areaLength - i - 1].value, areaNodes[areaLength - i - 2].address);
            }
            if (nextAreaAddress != -1)
                Console.WriteLine("{0:00000} {1:00000} {2:00000}", areaNodes[areaLength - i - 1].address, areaNodes[areaLength - i - 1].value, nextAreaAddress);
            else
                Console.WriteLine("{0:00000} {1:00000} {2}", areaNodes[areaLength - i - 1].address, areaNodes[areaLength - i - 1].value, nextAreaAddress);
        }

        public struct Node
        {
            public int address;
            public string value;
            public int next;
            public bool used;
        }
    }
}

放一个别人的C++版本的吧~~
#include<iostream>  
#include<vector>  
#include<cstdio>  
using namespace std;  
  
struct node  
{  
    int add;  
    int data;  
    int next;  
};  
int main()  
{  
    vector<node> vin(100000);//输入时暂存节点  
    vector<node> vsorted;//暂存排序后的结果  
    vector<node> vout;//最后的结果  
    node temp;  
    int first,N,K;  
  
    scanf("%d%d%d",&first,&N,&K);  
  
    for(int i = 0;i<N;i++)//输入  
    {  
        //cin>>temp.add>>temp.data>>temp.next;  
        scanf("%d%d%d",&temp.add,&temp.data,&temp.next);  
        vin[temp.add]=temp;  
    }  
    if(first == -1) //首地址为-1.直接输出  
    {  
        printf("-1\n");  
    }  
    else  
    {  
        int nextAdd = first;  
        while(nextAdd !=-1)  
        {  
            vsorted.push_back(vin[nextAdd]);  
            nextAdd = vin[nextAdd].next;  
        }  
        int Nnew = vsorted.size();//排序后的链的大小,不一定等于N,因为可能存在废点不在链上  
        int right = K-1;  
        while(right < Nnew)  
        {  
            for(int i=right;i>right-K;i--)  
            {  
                vout.push_back(vsorted[i]);  
            }  
            right += K;  
        }  
        for(int i = right-K+1;i<Nnew ;i++)  
        {  
            vout.push_back(vsorted[i]);  
        }  
        for(int i =0;i<Nnew-1;i++)  
        {  
            vout[i].next = vout[i+1].add;  
            printf("%05d %d %05d\n",vout[i].add,vout[i].data,vout[i].next);  
            //cout<<setw(5)<<setfill('0')<<vout[i].add<<" "<<vout[i].data<<" "<<setw(5)<<setfill('0')<<vout[i].next<<endl;  
        }  
        printf("%05d %d %d\n",vout[Nnew-1].add,vout[Nnew-1].data,-1);//最后地址-1 陷阱之一  
        //cout<<setw(5)<<setfill('0')<<vout[Nnew-1].add<<" "<<vout[Nnew-1].data<<" "<<vout[Nnew-1].next<<endl;  
    }  
    system("pause");  
    return 0;  
}