我试图解决这个问题：https://kth.kattis.com/problems/genealogical并且那里唯一的测试用例非常完美。但是，如果我在第一行写第三个生育线而在第三行写第一个生育线，则打印出这个：http://puu.sh/kJdBU/dcd693e466.png，顺序错误。如果这是我的代码，有谁知道为什么以及如何解决这个问题？
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Genealogical {
private static List<Person> persons = new ArrayList<Person>();
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
while (true) {
String firstLine = input.nextLine();
String[] splitted = firstLine.split(" : ");
if (splitted.length == 0) {
System.exit(0);
}
if (firstLine.contains("BIRTH") && splitted.length >= 2) {
String childName = splitted[0].substring(6);
if (splitted.length == 4) {
birth(childName, splitted[1], splitted[2], splitted[3]);
}
}
else if (firstLine.contains("DEATH")) {
if (!firstLine.contains(" : ")) {
if (persons.size() > 0)
persons.get(persons.size() - 1).kill(
firstLine.substring(6));
} else {
String name = splitted[0].substring(6);
getPerson(name).kill(splitted[1]);
}
}
else if (firstLine.contains("ANCESTORS")) {
String name = splitted[0].substring(10);
Person ancestor = getPerson(name);
for (Person p : persons) {
if (p.getName().equals(name) || p.used) {
continue;
}
else {
p.used = true;
ancestor.addAncestors(p);
}
}
}
else if (firstLine.contains("DESCENDANTS")) {
String name = splitted[0].substring(12);
Person descendant = getPerson(name);
for (Person p : persons) {
if (p.getName().equals(name) || p.used) {
continue;
}
else {
p.used = true;
descendant.addDescendants(p);
}
}
}
else if (firstLine.contains("QUIT")) {
if (persons.size() > 0) {
for (int i = persons.size() - 1; i >= 0; i--) {
Person p = persons.get(i);
if (p.getAncestors().size() > 0) {
printAncestor(p);
}
if (p.getDescendants().size() > 0) {
printDescendant(p);
}
}
}
System.exit(0);
}
}
}
public static void printAncestor(Person p) {
System.out.println("ANCESTORS of " + p.getName());
for (Person ancestor : p.getAncestors()) {
System.out.println(" " + ancestor.getName() + " "
+ ancestor.getDate() + " -" + ancestor.getDeathdate());
System.out.println(" " + ancestor.getDad().getName());
System.out.println(" " + ancestor.getMom().getName());
}
System.out.println();
}
public static void printDescendant(Person p) {
System.out.println("DESCENDANTS of " + p.getName());
for (Person descendant : p.getDescendants()) {
System.out.println(" " + descendant.getName() + " "
+ descendant.getDate() + " -" + descendant.getDeathdate());
}
}
private static void birth(String child, String date, String mother,
String father) {
Person mom = getPerson(mother);
if (mom == null) {
mom = new Person(null, null);
mom.setName(mother);
}
Person dad = getPerson(father);
if (dad == null) {
dad = new Person(null, null);
dad.setName(father);
}
Person childd = new Person(mom, dad);
childd.setName(child);
childd.setDate(date);
persons.add(childd);
}
private static Person getPerson(String person) {
for (Person p : persons) {
if (p.getName().equals(person)) {
return p;
}
}
return null;
}
}
这是我的人类：
import java.util.ArrayList;
import java.util.List;
public class Person {
private String name;
private String date;
private List<Person> children = new ArrayList<Person>();
private Person mom;
public boolean used = false;
private String deathDate = null;
private List<Person> ancestors = new ArrayList<Person>();
private List<Person> descendants = new ArrayList<Person>();
public Person getMom() {
return mom;
}
private Person dad;
public Person getDad() {
return dad;
}
public List<Person> getDescendants() {
return descendants;
}
public List<Person> getAncestors() {
return ancestors;
}
public Person(Person mom, Person dad)
{
this.mom = mom;
this.dad = dad;
}
public Person(String peo)
{
name = peo;
}
public void setName(String name)
{
this.name = name;
}
public String getName()
{
return this.name;
}
public void setDate(String date)
{
this.date = date;
}
public String getDate()
{
return this.date;
}
public void addChild(Person child)
{
children.add(child);
}
public void kill(String date)
{
this.deathDate = date;
}
public void addAncestors(Person p)
{
ancestors.add(p);
}
public void addDescendants(Person p)
{
descendants.add(p);
}
public String getDeathdate()
{
if(this.deathDate == null)
return "";
else
return " " + this.deathDate;
}
}
答案 0 :(得分：0)
保持命令的顺序，将它们保存在某处。
例如，你可以创建一个类，因为你已经解析了它：
public class OutputQuery
{
public final String command;
public final String name;
// Add other fields..
public OutputQuery(String command, String name)
{
this.command = command;
this.name = name;
}
}
在您的主类中添加一个List并将其添加到它：
private static List<OutputQuery> queries = new LinkedList<>();
// ...
else if (firstLine.contains("ANCESTORS"))
{
String name = splitted[0].substring(10);
queries.add(new OutputQuery("ANCESTORS", name));
//...
else if (firstLine.contains("DESCENDANTS"))
{
String name = splitted[0].substring(12);
queries.add(new OutputQuery("DESCENDANTS", name));
//...
else if (firstLine.contains("QUIT"))
{
for (OutputQuery query : queries)
{
if (query.command == "ANCESTORS")
{
// Print output
} else if (query.command == "DESCENDANTS")
{
// Print output
}
}
//...
你不需要遍历所有人，只需查询，正如你在上面的代码中看到的那样，查询循环不在另一个循环中，这里是完整的if if：
else if (firstLine.contains("QUIT"))
{
for (OutputQuery query : queries)
{
Person p = getPerson(query.name);
if (query.command == "ANCESTORS")
{
printAncestor(p);
} else if (query.command == "DESCENDANTS")
{
printDescendant(p);
}
}
System.exit(0);
}