UVA - 299 - Train Swapping (Java solution)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) throws IOException {
        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(isr);
        StringBuilder sb = new StringBuilder("");
        String m = "";
        int cases=Integer.parseInt(br.readLine());
        for(int i=0;i<cases;i++) {
            int num=Integer.parseInt(br.readLine());
            String[] str=br.readLine().split(" ");
            int[] arr=new int[num];
            for(int j=0;j<num;j++){
                arr[j]=Integer.parseInt(str[j]);
            }
            sb.append("Optimal train swapping takes ").append(numofSwap(arr)).append(" swaps.\n");
            }
        System.out.print(sb);
    }
   
    static int numofSwap(int []arr){
        int counter=0;
        for(int i=0;i<arr.length-1;i++){
            for(int j=i+1;j<arr.length;j++){
                if(arr[i]>arr[j]){
                    counter++;
                }
            }
        }
        return counter;
    }
}