How to sort an array in a single loop?
Last Updated :
12 Jul, 2025
Given an array of size N, the task is to sort this array using a single loop.
How the array is sorted usually?
There are many ways by which the array can be sorted in ascending order, like:
In any of these methods, more than 1 loops is used.
Can the array the sorted using a single loop?
Since all the known sorting methods use more than 1 loop, it is hard to imagine to do the same with a single loop. Practically, it is not impossible to do so. But doing so won't be the most efficient.
Example 1: Below code will sort an array with integer elements.
C++
// C++ code to sort an array of integers
// with the help of single loop
#include<bits/stdc++.h>
using namespace std;
// Function for Sorting the array
// using a single loop
int *sortArrays(int arr[], int length)
{
// Sorting using a single loop
for (int j = 0; j < length - 1; j++)
{
// Checking the condition for two
// simultaneous elements of the array
if (arr[j] > arr[j + 1])
{
// Swapping the elements.
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
// updating the value of j = -1
// so after getting updated for j++
// in the loop it becomes 0 and
// the loop begins from the start.
j = -1;
}
}
return arr;
}
// Driver code
int main()
{
// Declaring an integer array of size 11.
int arr[] = { 1, 2, 99, 9, 8,
7, 6, 0, 5, 4, 3 };
// Printing the original Array.
int length = sizeof(arr)/sizeof(arr[0]);
string str;
for (int i: arr)
{
str += to_string(i)+" ";
}
cout<<"Original array: ["
<< str << "]" << endl;
// Sorting the array using a single loop
int *arr1;
arr1 = sortArrays(arr, length);
// Printing the sorted array.
string str1;
for (int i = 0; i < length; i++)
{
str1 += to_string(arr1[i])+" ";
}
cout << "Sorted array: ["
<< (str1) << "]";
}
// This code is contributed by Rajout-Ji
// Java code to sort an array of integers
// with the help of single loop
import java.util.*;
class Geeks_For_Geeks {
// Function for Sorting the array
// using a single loop
public static int[] sortArrays(int[] arr)
{
// Finding the length of array 'arr'
int length = arr.length;
// Sorting using a single loop
for (int j = 0; j < length - 1; j++) {
// Checking the condition for two
// simultaneous elements of the array
if (arr[j] > arr[j + 1]) {
// Swapping the elements.
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
// updating the value of j = -1
// so after getting updated for j++
// in the loop it becomes 0 and
// the loop begins from the start.
j = -1;
}
}
return arr;
}
// Declaring main method
public static void main(String args[])
{
// Declaring an integer array of size 11.
int arr[] = { 1, 2, 99, 9, 8,
7, 6, 0, 5, 4, 3 };
// Printing the original Array.
System.out.println("Original array: "
+ Arrays.toString(arr));
// Sorting the array using a single loop
arr = sortArrays(arr);
// Printing the sorted array.
System.out.println("Sorted array: "
+ Arrays.toString(arr));
}
}
# Python3 code to sort an array of integers
# with the help of single loop
# Function for Sorting the array
# using a single loop
def sortArrays(arr):
# Finding the length of array 'arr'
length = len(arr)
# Sorting using a single loop
j = 0
while j < length - 1:
# Checking the condition for two
# simultaneous elements of the array
if (arr[j] > arr[j + 1]):
# Swapping the elements.
temp = arr[j]
arr[j] = arr[j + 1]
arr[j + 1] = temp
# updating the value of j = -1
# so after getting updated for j++
# in the loop it becomes 0 and
# the loop begins from the start.
j = -1
j += 1
return arr
# Driver Code
if __name__ == '__main__':
# Declaring an integer array of size 11.
arr = [1, 2, 99, 9, 8,
7, 6, 0, 5, 4, 3]
# Printing the original Array.
print("Original array: ", arr)
# Sorting the array using a single loop
arr = sortArrays(arr)
# Printing the sorted array.
print("Sorted array: ", arr)
# This code is contributed by Mohit Kumar
// C# code to sort an array of integers
// with the help of single loop
using System;
class GFG
{
// Function for Sorting the array
// using a single loop
public static int[] sortArrays(int[] arr)
{
// Finding the length of array 'arr'
int length = arr.Length;
// Sorting using a single loop
for (int j = 0; j < length - 1; j++)
{
// Checking the condition for two
// simultaneous elements of the array
if (arr[j] > arr[j + 1])
{
// Swapping the elements.
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
// updating the value of j = -1
// so after getting updated for j++
// in the loop it becomes 0 and
// the loop begins from the start.
j = -1;
}
}
return arr;
}
// Driver Code
public static void Main(String []args)
{
// Declaring an integer array of size 11.
int []arr = { 1, 2, 99, 9, 8,
7, 6, 0, 5, 4, 3 };
// Printing the original Array.
Console.WriteLine("Original array: " +
String.Join(", ", arr));
// Sorting the array using a single loop
arr = sortArrays(arr);
// Printing the sorted array.
Console.WriteLine("Sorted array: " +
String.Join(", ", arr));
}
}
// This code is contributed by Rajput-Ji
<script>
// Javascript code to sort an array of integers
// with the help of single loop
// Function for Sorting the array
// using a single loop
function sortArrays(arr)
{
// Finding the length of array 'arr'
let length = arr.length;
// Sorting using a single loop
for (let j = 0; j < length - 1; j++) {
// Checking the condition for two
// simultaneous elements of the array
if (arr[j] > arr[j + 1]) {
// Swapping the elements.
let temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
// updating the value of j = -1
// so after getting updated for j++
// in the loop it becomes 0 and
// the loop begins from the start.
j = -1;
}
}
return arr;
}
// Declaring main method
let arr=[1, 2, 99, 9, 8,
7, 6, 0, 5, 4, 3];
document.write("Original array: ["
+ (arr).join(", ")+"]<br>");
// Sorting the array using a single loop
arr = sortArrays(arr);
// Printing the sorted array.
document.write("Sorted array: ["
+ arr.join(", ")+"]<br>");
// This code is contributed by patel2127
</script>
Output: Original array: [1, 2, 99, 9, 8, 7, 6, 0, 5, 4, 3]
Sorted array: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 99]
Example 2: Below code will sort an array of Strings.
C++
// C++ code to sort an array of Strings
// with the help of single loop
#include<bits/stdc++.h>
using namespace std;
// Function for Sorting the array using a single loop
char* sortArrays(char arr[], int length)
{
// Sorting using a single loop
for (int j = 0; j < length - 1; j++)
{
// Type Conversion of char to int.
int d1 = arr[j];
int d2 = arr[j + 1];
// Comparing the ascii code.
if (d1 > d2)
{
// Swapping of the characters
char temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
j = -1;
}
}
return arr;
}
// Driver code
int main()
{
// Declaring a String
string geeks = "GEEKSFORGEEKS";
int n = geeks.length();
// declaring character array
char arr[n];
// copying the contents of the
// string to char array
for(int i = 0; i < n; i++)
{
arr[i] = geeks[i];
}
// Printing the original Array.
cout<<"Original array: [";
for(int i = 0; i < n; i++)
{
cout << arr[i];
if(i + 1 != n)
cout<<", ";
}
cout << "]" << endl;
// Sorting the array using a single loop
char *ansarr;
ansarr = sortArrays(arr, n);
// Printing the sorted array.
cout << "Sorted array: [";
for(int i = 0; i < n; i++)
{
cout << ansarr[i];
if(i + 1 != n)
cout << ", ";
}
cout << "]" << endl;
}
// This code is contributed by Rajput-Ji
// Java code to sort an array of Strings
// with the help of single loop
import java.util.*;
class Geeks_For_Geeks {
// Function for Sorting the array using a single loop
public static char[] sortArrays(char[] arr)
{
// Finding the length of array 'arr'
int length = arr.length;
// Sorting using a single loop
for (int j = 0; j < arr.length - 1; j++) {
// Type Conversion of char to int.
int d1 = arr[j];
int d2 = arr[j + 1];
// Comparing the ascii code.
if (d1 > d2) {
// Swapping of the characters
char temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
j = -1;
}
}
return arr;
}
// Declaring main method
public static void main(String args[])
{
// Declaring a String
String geeks = "GEEKSFORGEEKS";
// Declaring a character array
// to store characters of geeks in it.
char arr[] = geeks.toCharArray();
// Printing the original Array.
System.out.println("Original array: "
+ Arrays.toString(arr));
// Sorting the array using a single loop
arr = sortArrays(arr);
// Printing the sorted array.
System.out.println("Sorted array: "
+ Arrays.toString(arr));
}
}
# Python3 code to sort an array of Strings
# with the help of single loop
# Function for Sorting the array using a single loop
def sortArrays(arr, length):
# Sorting using a single loop
j = 0
while(j < length - 1):
# Type Conversion of char to int.
d1 = arr[j]
d2 = arr[j + 1]
# Comparing the ascii code.
if (d1 > d2):
# Swapping of the characters
temp = arr[j]
arr[j] = arr[j + 1]
arr[j + 1] = temp
j = -1
j += 1
return arr
# Driver code
# Declaring a String
geeks = "GEEKSFORGEEKS"
n = len(geeks)
# declaring character array
arr=[0]*n
# copying the contents of the
# string to char array
for i in range(n):
arr[i] = geeks[i]
# Printing the original Array.
print("Original array: [",end="")
for i in range(n):
print(arr[i],end="")
if (i + 1 != n):
print(", ",end="")
print("]")
# Sorting the array using a single loop
ansarr = sortArrays(arr, n)
# Printing the sorted array.
print("Sorted array: [",end="")
for i in range(n):
print(ansarr[i],end="")
if (i + 1 != n):
print(", ",end="")
print("]")
# This code is contributed by shubhamsingh10
// C# code to sort an array of Strings
// with the help of single loop
using System;
class GFG
{
// Function for Sorting the array
// using a single loop
public static char[] sortArrays(char[] arr)
{
// Finding the length of array 'arr'
int length = arr.Length;
// Sorting using a single loop
for (int j = 0; j < arr.Length - 1; j++)
{
// Type Conversion of char to int.
int d1 = arr[j];
int d2 = arr[j + 1];
// Comparing the ascii code.
if (d1 > d2)
{
// Swapping of the characters
char temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
j = -1;
}
}
return arr;
}
// Declaring main method
public static void Main(String []args)
{
// Declaring a String
String geeks = "GEEKSFORGEEKS";
// Declaring a character array
// to store characters of geeks in it.
char []arr = geeks.ToCharArray();
// Printing the original Array.
Console.WriteLine("Original array: [" +
String.Join(", ", arr) + "]");
// Sorting the array using a single loop
arr = sortArrays(arr);
// Printing the sorted array.
Console.WriteLine("Sorted array: [" +
String.Join(", ", arr) + "]");
}
}
// This code is contributed by PrinciRaj1992
<script>
// JavaScript code to sort an array of integers
// with the help of single loop
// Function for Sorting the array
// using a single loop
function sortArrays(arr)
{
// Finding the length of array 'arr'
let length = arr.length;
// Sorting using a single loop
for (let j = 0; j < length - 1; j++)
{
// Type Conversion of char to int.
let d1 = arr[j];
let d2 = arr[j + 1];
// Comparing the ascii code.
if (d1 > d2)
{
// Swapping of the characters
let temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
j = -1;
}
}
return arr;
}
// Declaring a String
let geeks = "GEEKSFORGEEKS";
// Declaring a character array
// to store characters of geeks in it.
let arr = geeks.split("");
document.write("Original array: ["
+ arr.join(", ")+"]<br>");
// Sorting the array using a single loop
arr = sortArrays(arr);
// Printing the sorted array.
document.write("Sorted array: ["
+ (arr).join(", ")+"]<br>");
// This code is contributed by shivanisinghss2110
</script>
Output: Original array: [G, E, E, K, S, F, O, R, G, E, E, K, S]
Sorted array: [E, E, E, E, F, G, G, K, K, O, R, S, S]
Is sorting array in single loop better than sorting in more than one loop?
Sorting in a single loop, though it seems to be better, is not an efficient approach. Below are some points to be taken into consideration before using single loop sorting:
- Using a single loop only helps in shorter code
- The time complexity of the sorting does not change in a single loop (in comparison to more than one loop sorting)
- Single loop sorting shows that number of loops has little to do with time complexity of the algorithm.
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