minimumswap.java

//https://www.hackerrank.com/challenges/minimum-swaps-2/problem?h_l=interview&playlist_slugs%5B%5D%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D%5B%5D=arrays&isFullScreen=true

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Solution {

    // Complete the minimumSwaps function below.
    static int minimumSwaps(int[] arr) {
        boolean visited[] = new boolean[arr.length+1];
        HashMap<Integer,Integer> table = new HashMap<Integer,Integer>();
        for(int i=1;i<visited.length;i++)
            table.put(i,arr[i-1]);
        int count = 0;
        for(int i=1;i<table.size();i++){
            if(visited[i] == false)
                visited[i] = true;
            if(i!=table.get(i))
            {
                int c = table.get(i);
                while(!visited[c]){
                    visited[c] = true;
                    count++;
                    int next = table.get(c);
                    c = next;
                }
            }
        }
        return count;

    }

    private static final Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) throws IOException {
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int n = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

        int[] arr = new int[n];

        String[] arrItems = scanner.nextLine().split(" ");
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

        for (int i = 0; i < n; i++) {
            int arrItem = Integer.parseInt(arrItems[i]);
            arr[i] = arrItem;
        }

        int res = minimumSwaps(arr);

        bufferedWriter.write(String.valueOf(res));
        bufferedWriter.newLine();

        bufferedWriter.close();

        scanner.close();
    }
}