Reversing Linked List

Given a constant K and a singly linked list L, you are supposed to reverse the links of every K elements on L. For example, given L being 1→2→3→4→5→6, if K=3, then you must output 3→2→1→6→5→4; if K=4, you must output 4→3→2→1→5→6.

Input Specification:

Each input file contains one test case. For each case, the first line contains the address of the first node, a positive N (≤105) which is the total number of nodes, and a positive K (≤N) which is the length of the sublist to be reversed. The address of a node is a 5-digit nonnegative integer, and NULL is represented by -1.

Then N lines follow, each describes a node in the format:
Address Data Next
where Address is the position of the node, Data is an integer, and Next is the position of the next node.

Output Specification:

For each case, output the resulting ordered linked list. Each node occupies a line, and is printed in the same format as in the input.

Sample Input:
00100 6 4
00000 4 99999
00100 1 12309
68237 6 -1
33218 3 00000
99999 5 68237
12309 2 33218
Sample Output:
00000 4 33218
33218 3 12309
12309 2 00100
00100 1 99999
99999 5 68237
68237 6 -1
代码长度限制

16 KB

时间限制

400 ms

内存限制

64 MB


import java.util.*;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);String startPoint = sc.next();int pointNum = sc.nextInt();int k = sc.nextInt();ArrayList<list> list = new ArrayList<>();for (int i = 0; i < pointNum; i++) {list.add(new list(sc.next(),sc.nextInt(),sc.next()));}list.sort(new Comparator<Main.list>() {@Overridepublic int compare(Main.list o1, Main.list o2) {return o1.getData() - o2.getData();}});if (pointNum % k == 0 && k != 1) {Collections.reverse(list.subList(0,k));Collections.reverse(list.subList(k,pointNum));for (int i = 1; i < list.size(); i++) {list.get(i - 1).setNextAddress(list.get(i).getAddress());}list.get(pointNum - 1).setNextAddress("-1");for (int i = 0; i < list.size(); i++) {System.out.println(list.get(i).toString());}} else {Collections.reverse(list.subList(0,k));for (int i = 1; i < list.size(); i++) {list.get(i - 1).setNextAddress(list.get(i).getAddress());}for (int i = 0; i < list.size(); i++) {System.out.println(list.get(i).toString());}}}static class list {String address;int data;String nextAddress;public list(String address, int data, String nextAddress) {this.address = address;this.data = data;this.nextAddress = nextAddress;}public String getAddress() {return address;}public int getData() {return data;}public String getNextAddress() {return nextAddress;}public void setAddress(String address) {this.address = address;}public void setData(int data) {this.data = data;}public void setNextAddress(String nextAddress) {this.nextAddress = nextAddress;}@Overridepublic String toString() {returnaddress + ' ' + data + ' ' + nextAddress;}}
}