String replacement related topics (merging arrays)

1、 Title Description ：
There are two sort arrays A1 and A2, In memory A1 There is enough free space at the end of the to accommodate A2. Please implement a function , hold A2 Insert all numbers in... Into A1 in , And all the numbers are sorted .
2、 The test case

3、 Solutions
Train of thought ： Scan string from beginning to end , Replace every time you encounter a space character . But because it is 1 Replace the characters with 3 Characters , You have to move all the characters after the space back 2 byte .
Train of thought two ： Merging two arrays （ Including strings ） when , If you assign each number from front to back （ Or character ）, You need to move the number repeatedly （ Or character ） many times , So we can consider copying from the back to the front , This reduces the number of moves , To improve efficiency .
Complexity analysis ： Time complexity O(N^2)
The code is as follows ：

#include <stdio.h>
#include <string.h>

void Unite_Arry(int *arrA, int *arrB, int len1, int len2)
{
    
	// Create a new array , Used to store the reorganized elements 
	int arrC[30] = {
    0};
	//arrC Length of array 
	int len3 = len1 + len2;
	int len = len3;
	// Enter judgment 
	if(NULL == arrA || NULL == arrB || (len1-1) < 0 || (len2-1) < 0)
	{
    
		printf("The input parameter error!\n");
		return;
	}
	// Start array reorganization 
	while((len1-1) >= 0 && (len2-1) >= 0)
	{
    
		if(arrA[len1-1] >= arrB[len2-1])
		{
    
			arrC[lem3-1] = arrA[len1-1];
			len1--;
			len3--;
		}
		else
		{
    
			arrC[len3-1] = arrB[len2-1];
			len2--;
			len3--;
		}
	}
	// When arrA Element ratio of array arrB When there are many elements in the array , Copy the extra elements directly to arrC Foremost 
	if(len1 > 0)
	{
    
		memcpy(arrC, arrA, len1*sizeof(int));
	}
	// When arrB Element ratio of array arrA When there are many elements in the array , Copy the extra elements directly to arrC Foremost 
 	if(len2 > 0)
 	{
    
  		memcpy(arrC, arrB, len2*sizeof(int));
 	}
 	// Output the reorganized array 
 	int i;
 	printf("Reorganized arrC is：");
 	for(i=0;i<len;i++)
 	{
    
 		printf("%d ", arrC[i]);
 	}
 	printf("\n");
 }

int main()
{
    
	int arrA[] = {
    1,3,6,9,10};
	int arrB[] = {
    0,1,2,12};
	int n,m;
	printf("Original arrA is：");
	for(n=0; n<sizeof(arrA)/sizeof(int); n++)
	{
    
		printf("%d ", arrA[n]);
	}
	printf("\n");
	printf("Original arrB is：");
	for(m=0; m<sizeof(arrB)/sizeof(int); m++)
	{
    
		printf("%d ", arrB[m]);
	}
	printf("\n");
	Unite_Arry((int*)arrA, (int*)arrB, sizeof(arrA)/sizeof(int), sizeof(arrB)/sizeof(int));

	return 0;
}