我正在努力解决Java中一个非常简单的问题。我已经在 java 中实现了快速排序,它适用于数组列表并且可以接受任何值。问题是它仅适用于小于约 8000 大小的数组列表。谁能告诉我我的程序出了什么问题?我认为它可能与递归深度限制有关,但我不确定(因为有时它适用于更大的尺寸,有时不适用于(。如何改进我的快速排序实现,使其适用于更大尺寸的 Arraylist,如 100000?
import java.util.ArrayList;
import java.util.Random;
public class QuickSort {
Random gener;
int temporary,genertype,NInts,flag;
ArrayList<Integer> mylist;
public QuickSort(int type,int ilosc){
gener = new Random();
mylist= new ArrayList<>();
this.genertype=type;
this.NInts=ilosc;
}
void generate(){
if(genertype==0){
for(int i=0;i<NInts;i++){
mylist.add(gener.nextInt(100000));
}
}else {
for(int i=0;i<NInts;i++){
mylist.add(NInts-i);
}
}
}
int count1(ArrayList<Integer> list,int counter1,int counter2){
while(list.get(0)<list.get(counter1)){
if(counter1==counter2){
flag=1;
return counter1;
}
counter1++;
}
flag=0;
return counter1;
}
int count2(ArrayList<Integer> list,int counter1,int counter2){
while(list.get(0)>list.get(counter2)){
if(counter1==counter2){
flag=1;
return counter2;
}
counter2--;
}
flag=0;
return counter2;
}
public ArrayList<Integer> sorting(ArrayList<Integer> list) {
ArrayList<Integer> left = new ArrayList<Integer>();
ArrayList<Integer> right = new ArrayList<Integer>();
int counter1,counter2;
if (list.size() == 1) {
return list;
}else {
counter1=1;
counter2=list.size()-1;
while(counter1!=counter2) {
counter1=count1(list,counter1,counter2);
if(flag==1)
break;
counter2=count2(list,counter1,counter2);
if(flag==1)
break;
temporary = list.get(counter1);
list.set(counter1, list.get(counter2));
list.set(counter2, temporary);
}
for (int i = 0; i < counter1; i++) {
left.add(list.get(i));
}
for (int i = counter1; i < list.size(); i++) {
right.add(list.get(i));
}
left = sorting(left);
right = sorting(right);
list=merge(left, right);
}
return list;
}
ArrayList<Integer> merge(ArrayList<Integer> left, ArrayList<Integer> right) {
if(left.get(0)>right.get(right.size()-1)){
right.addAll(left);
return right;
}
else{
left.addAll(right);
return left;
}
}
void printing(){
for(int k=0;k<NInts;k++){
System.out.print(" "+mylist.get(k));
}
}
public static void main(String[] args){
QuickSort instance = new QuickSort(1,1000);
instance.generate();
instance.mylist=instance.sorting(instance.mylist);
instance.printing();
}
}
Ps.如果您在我的代码中发现任何错误,请告诉我,以便我改进它:)
代码无法针对大量输入运行的原因可能有很多。大多数情况下,这可能是因为为应用程序指定的堆大小容量溢出。这可以通过增加应用程序的堆大小来解决(查看此堆栈溢出链接,了解如何增加应用程序的堆大小(