在一个数组中排序合并

给定两个排序数组 A 和 B，其中 A 在末尾有足够大的缓冲区来容纳 B。
按排序顺序将 B 合并到 A 中。
例子：

Input : a[] = {10, 12, 13, 14, 18, NA, NA, NA, NA, NA}   
        b[] = {16, 17, 19, 20, 22};;
Output : a[] = {10, 12, 13, 14, 16, 17, 18, 19, 20, 22}

一种方法是通过将较小的元素插入到 A 的前面来合并两个数组，但这种方法的问题是我们必须在每次插入后将每个元素向右移动。
因此，我们可以比较哪个更大，然后将该元素插入到 A 的末尾，而不是比较哪个是较小的元素。
以下是上述方法的解决方案。

C++

// Merging b[] into a[]
#include 
using namespace std;
#define NA -1
 
void sortedMerge(int a[], int b[], int n, int m) {
  int i = n - 1;
  int j = m - 1;
 
  int lastIndex = n + m - 1;
 
  /* Merge a and b, starting from last element
     in each */
  while (j >= 0) {
 
    /* End of a is greater than end of b */
    if (i >= 0 && a[i] > b[j]) {
      a[lastIndex] = a[i]; // Copy Element
      i--;
    } else {
      a[lastIndex] = b[j]; // Copy Element
      j--;
    }
    lastIndex--; // Move indices
  }
}
 
/* Helper function to print the array */
void printArray(int *arr, int n) {
  cout << "Array A after merging B in sorted"
        " order : " << endl;
  for (int i = 0; i < n; i++)
    cout << arr[i] << " ";
}
 
int main() {
  int a[] = {10, 12, 13, 14, 18, NA, NA, NA, NA, NA};
  int n = 5;
  int size_a = 10;
  int b[] = {16, 17, 19, 20, 22};
  int m = 5;
  sortedMerge(a, b, n, m);
  printArray(a, size_a);
  return 0;
}

Java

// Java  program to merge B
// into A in sorted order.
import java.io.*;
 
class GFG
{
    static int NA =-1;
    static void sortedMerge(int a[], int b[], int n, int m)
    {
        int i = n - 1;
        int j = m - 1;
         
        int lastIndex = n + m - 1;
         
        // Merge a and b, starting
        // from last element in each
        while (j >= 0)
        {
         
            /* End of a is greater than end of b */
            if (i >= 0 && a[i] > b[j])
            {
                // Copy Element
                a[lastIndex] = a[i];
                i--;
            } else
            { 
                // Copy Element
                a[lastIndex] = b[j];
                j--;
            }
            // Move indices
            lastIndex--;
        }
    }
     
    // Helper function to print the array
    static void printArray(int arr[], int n)
    {
        System.out.println ( "Array A after merging B in sorted order : " ) ;
        for (int i = 0; i < n; i++)
            System.out.print(arr[i] +" ");
    }
     
    // Driver code
    public static void main (String[] args)
    {
        int a[] = {10, 12, 13, 14, 18, NA, NA, NA, NA, NA};
        int n = 5;
        int size_a = 10;
        int b[] = {16, 17, 19, 20, 22};
        int m = 5;
        sortedMerge(a, b, n, m);
        printArray(a, size_a);
    }
}
 
// This code is contributed by vt_m.

Python3

# Python3 program to merge B
# into A in sorted order.
 
NA = -1
 
# Merging b[] into a[]
def sortedMerge(a, b, n, m):
 
    i = n - 1
    j = m - 1
     
    lastIndex = n + m - 1
     
    # Merge a and b, starting from last
    # element in each
    while (j >= 0) :
     
        # End of a is greater than end
        # of b
        if (i >= 0 and a[i] > b[j]):
             
            # Copy Element
            a[lastIndex] = a[i]
            i -= 1
        else:
             
             # Copy Element
            a[lastIndex] = b[j]
            j -= 1
         
        # Move indices
        lastIndex-= 1
 
# Helper function to print
# the array
def printArray(arr, n):
 
    print("Array A after merging B in sorted order : ")
 
    for i in range(0, n):
        print(arr[i], end =" ")
 
size_a = 10
 
a = [10, 12, 13, 14, 18, NA, NA, NA, NA, NA]
n = 5
 
b = [16, 17, 19, 20, 22]
m = 5
 
sortedMerge(a, b, n, m)
printArray(a, size_a)
 
# This code is contributed by
# Smitha Dinesh Semwal

C#

// C# program to merge B into A in
// sorted order.
using System;
 
class GFG {
     
    static int NA =-1;
    static void sortedMerge(int []a, int []b,
                                 int n, int m)
    {
        int i = n - 1;
        int j = m - 1;
         
        int lastIndex = n + m - 1;
         
        // Merge a and b, starting
        // from last element in each
        while (j >= 0)
        {
         
            /* End of a is greater than
            end of b */
            if (i >= 0 && a[i] > b[j])
            {
                 
                // Copy Element
                a[lastIndex] = a[i];
                i--;
            }
             
            else
            {
                 
                // Copy Element
                a[lastIndex] = b[j];
                j--;
            }
             
            // Move indices
            lastIndex--;
        }
    }
     
    // Helper function to print the array
    static void printArray(int []arr, int n)
    {
         
        Console.WriteLine ( "Array A after "
        + "merging B in sorted order : " ) ;
         
        for (int i = 0; i < n; i++)
            Console.Write(arr[i] +" ");
    }
     
    // Driver code
    public static void Main ()
    {
        int []a = {10, 12, 13, 14, 18, NA,
                           NA, NA, NA, NA};
        int n = 5;
        int size_a = 10;
        int []b = {16, 17, 19, 20, 22};
        int m = 5;
         
        sortedMerge(a, b, n, m);
         
        printArray(a, size_a);
    }
}
 
// This code is contributed by vt_m.

PHP

= 0)
    {
     
        /* End of a is greater than end of b */
        if ($i >= 0 && $a[$i] > $b[$j])
        {
            $a[$lastIndex] = $a[$i]; // Copy Element
            $i--;
        }
        else
        {
            $a[$lastIndex] = $b[$j]; // Copy Element
            $j--;
        }
        $lastIndex--; // Move indices
    }
    return $a;
}
 
/* Helper function to print the array */
function printArray($arr, $n)
{
    echo "Array A after merging B in sorted";
        echo " order : \n";
    for ($i = 0; $i < $n; $i++)
        echo $arr[$i] . " ";
}
 
// Driver Code
$a = array(10, 12, 13, 14, 18,
          -1, -1, -1, -1, -1);
$n = 5;
$size_a = 10;
 
$b = array(16, 17, 19, 20, 22);
$m = 5;
$c = sortedMerge($a, $b, $n, $m);
printArray($c, $size_a);
 
// This code is contributed by Rajput-Ji.
?>

Javascript

// Javascript program to merge B into A in
// sorted order.
 
// Merging b[] into a[]
function sortedMerge(a, b, n, m) {
    let i = n - 1;
    let j = m - 1;
 
    let lastIndex = n + m - 1;
 
    /* Merge a and b, starting from
    last element in each */
    while (j >= 0) {
 
        /* End of a is greater than end of b */
        if (i >= 0 && a[i] > b[j]) {
            a[lastIndex] = a[i]; // Copy Element
            i--;
        }
        else {
            a[lastIndex] = b[j]; // Copy Element
            j--;
        }
        lastIndex--; // Move indices
    }
    return a;
}
 
/* Helper function to print the array */
function printArray(arr, n) {
    document.write("Array A after merging B in sorted");
    document.write(" order : <br>");
    for (let i = 0; i < n; i++)
        document.write(arr[i] + " ");
}
 
// Driver Code
let a = [10, 12, 13, 14, 18,
    -1, -1, -1, -1, -1];
let n = 5;
let size_a = 10;
 
let b = new Array(16, 17, 19, 20, 22);
let m = 5;
let c = sortedMerge(a, b, n, m);
printArray(c, size_a);
 
// This code is contributed by gfgking.

输出：

Array A after merging B in sorted order : 
10 12 13 14 16 17 18 19 20 22

时间复杂度为 O(m+n)。