sorting integers in order lowest to highest java
These numbers are stored in the same integer variable. How would I go about sorting the integers in order lowest to highest?
11367 11358 11421 11530 11开发者_JAVA技巧491 11218 11789
There are two options, really:
- Use standard collections, as explained by Shakedown
- Use Arrays.sort
E.g.,
int[] ints = {11367, 11358, 11421, 11530, 11491, 11218, 11789};
Arrays.sort(ints);
System.out.println(Arrays.asList(ints));
That of course assumes that you already have your integers as an array. If you need to parse those first, look for String.split and Integer.parseInt.
You can put them into a list and then sort them using their natural ordering, like so:
final List<Integer> list = Arrays.asList(11367, 11358, 11421, 11530, 11491, 11218, 11789);
Collections.sort( list );
// Use the sorted list
If the numbers are stored in the same variable, then you'll have to somehow put them into a List
and then call sort
, like so:
final List<Integer> list = new ArrayList<Integer>();
list.add( myVariable );
// Change myVariable to another number...
list.add( myVariable );
// etc...
Collections.sort( list );
// Use the sorted list
Collections.sort( List )
Well, if you want to do it using an algorithm. There are a plethora of sorting algorithms out there. If you aren't concerned too much about efficiency and more about readability and understandability. I recommend Insertion Sort. Here is the psudo code, it is trivial to translate this into java.
begin
for i := 1 to length(A)-1 do
begin
value := A[i];
j := i - 1;
done := false;
repeat
{ To sort in descending order simply reverse
the operator i.e. A[j] < value }
if A[j] > value then
begin
A[j + 1] := A[j];
j := j - 1;
if j < 0 then
done := true;
end
else
done := true;
until done;
A[j + 1] := value;
end;
end;
For sorting narrow range of integers try Counting sort, which has a complexity of O(range + n)
, where n
is number of items to be sorted. If you'd like to sort something not discrete use optimal n*log(n) algorithms (quicksort, heapsort, mergesort). Merge sort is also used in a method already mentioned by other responses Arrays.sort
. There is no simple way how to recommend some algorithm or function call, because there are dozens of special cases, where you would use some sort, but not the other.
So please specify the exact purpose of your application (to learn something (well - start with the insertion sort or bubble sort), effectivity for integers (use counting sort), effectivity and reusability for structures (use n*log(n) algorithms), or zou just want it to be somehow sorted - use Arrays.sort :-)). If you'd like to sort string representations of integers, than u might be interrested in radix sort....
import java.util.Arrays;
public class sortNumber {
public static void main(String[] args) {
// Our array contains 13 elements
int[] array = {9, 238, 248, 138, 118, 45, 180, 212, 103, 230, 104, 41, 49};
Arrays.sort(array);
System.out.printf(" The result : %s", Arrays.toString(array));
}
}
if array.sort doesn't have what your looking for you can try this:
package drawFramePackage;
import java.awt.geom.AffineTransform;
import java.util.ArrayList;
import java.util.ListIterator;
import java.util.Random;
public class QuicksortAlgorithm {
ArrayList<AffineTransform> affs;
ListIterator<AffineTransform> li;
Integer count, count2;
/**
* @param args
*/
public static void main(String[] args) {
new QuicksortAlgorithm();
}
public QuicksortAlgorithm(){
count = new Integer(0);
count2 = new Integer(1);
affs = new ArrayList<AffineTransform>();
for (int i = 0; i <= 128; i++){
affs.add(new AffineTransform(1, 0, 0, 1, new Random().nextInt(1024), 0));
}
affs = arrangeNumbers(affs);
printNumbers();
}
public ArrayList<AffineTransform> arrangeNumbers(ArrayList<AffineTransform> list){
while (list.size() > 1 && count != list.size() - 1){
if (list.get(count2).getTranslateX() > list.get(count).getTranslateX()){
list.add(count, list.get(count2));
list.remove(count2 + 1);
}
if (count2 == list.size() - 1){
count++;
count2 = count + 1;
}
else{
count2++;
}
}
return list;
}
public void printNumbers(){
li = affs.listIterator();
while (li.hasNext()){
System.out.println(li.next());
}
}
}
Take Inputs from User and Insertion Sort. Here is how it works:
package com.learning.constructor;
import java.util.Scanner;
public class InsertionSortArray {
public static void main(String[] args) {
Scanner s=new Scanner(System.in);
System.out.println("enter number of elements");
int n=s.nextInt();
int arr[]=new int[n];
System.out.println("enter elements");
for(int i=0;i<n;i++){//for reading array
arr[i]=s.nextInt();
}
System.out.print("Your Array Is: ");
//for(int i: arr){ //for printing array
for (int i = 0; i < arr.length; i++){
System.out.print(arr[i] + ",");
}
System.out.println("\n");
int[] input = arr;
insertionSort(input);
}
private static void printNumbers(int[] input) {
for (int i = 0; i < input.length; i++) {
System.out.print(input[i] + ", ");
}
System.out.println("\n");
}
public static void insertionSort(int array[]) {
int n = array.length;
for (int j = 1; j < n; j++) {
int key = array[j];
int i = j-1;
while ( (i > -1) && ( array [i] > key ) ) {
array [i+1] = array [i];
i--;
}
array[i+1] = key;
printNumbers(array);
}
}
}
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