如何在单个循环中对数组排序？

给定大小为N的数组，任务是使用单个循环对该数组进行排序。

通常如何排序数组?
可以采用多种方式对数组进行升序排序，例如：

• 选择排序
• 二进制排序
• 合并排序
• 基数排序
• 插入排序等

在这些方法中的任何一种中，都使用了1个以上的循环。

可以使用单个循环对数组进行排序吗?
由于所有已知的排序方法都使用不止1个循环，因此很难想象对一个循环进行相同的处理。实际上，这样做并非没有可能。但是这样做并不是最有效的。

示例1：下面的代码将对具有整数元素的数组进行排序。

C++

// C++ code to sort an array of integers
// with the help of single loop
#include
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

// 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

# 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#

// 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

输出：

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]

示例2：下面的代码将对字符串数组进行排序。

C++

// C++ code to sort an array of Strings
// with the help of single loop
#include
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

// 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

# 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＃

// 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

输出：

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]

在单循环中排序数组比在多个循环中排序数组好吗?
尽管看起来更好，但在单个循环中进行排序并不是一种有效的方法。在使用单循环排序之前，需要考虑以下几点：

• 使用单个循环只会帮助缩短代码
• 排序的时间复杂度不会在单个循环中发生变化(与多个循环排序相比)
• 单循环排序显示循环次数与算法的时间复杂度几乎没有关系。