Find Maximum number possible by doing at-most K swaps (Stuck in the problem )

help
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1

Find Maximum number possible by doing at-most K swaps

Given a positive integer, find the maximum integer possible by doing at-most K swap operations on its digits.
Examples:

Input: M = 254, K = 1 Output: 524
Swap 5 with 2 so number becomes 524
Input: M = 254, K = 2 Output:
542 Swap 5 with 2 so number becomes 524
Swap 4 with 2 so number becomes 542

MY CODE
public static void main(String[] args) {

    int[] arr= {2,4,5};
	System.out.println(MaxNum(arr,1));

}

public static int MaxNum(int[] arr, int s) {

     int[] strg=new int[arr.length];

	if(s<1)
	return 0;

	int ans=0;
	for (int k = 1; k <arr.length; k++) {
		
		
		strg = swap(arr, k, 0);
		ans=Math.max(strg[0],arr[0]);
	    MaxNum(strg, s-1);
		swap(arr, k, 0);
		
		

	}
	
	
		for(int val:strg)
			System.out.print(val+".  strg.   ");
	
	
	
	return ans;

}

public static int[] swap(int[] arr, int a, int b) {

	int temp = arr[a];
	arr[a] = arr[b];
	arr[b] = temp;

	return arr;

}

I am not sure if my approach is right . Also in above code I am not able to print full array with max number so I have just compared the 0th index (just for now).
How do I print the array with max number? please help

2

You can just sort the array and then rearrange it so that the largest number comes first and then the second largest number and then accordingly using java.util.Arrays.sort(Object[] a, int fromIndex, int toIndex) , I use C++ so this is equivalent to sort(a,a+n) (where a is the array of size n) and this STL sorts the array in ascending order.
Hope this helps!!

3

if we sort then how we will take care of K operation. the sorting will give the biggest number possible . can you help me with printing the array after K operations using recursion which I am using above in the code