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MinimumSwaps2.java
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MinimumSwaps2.java
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// https://www.hackerrank.com/challenges/minimum-swaps-2/problem
package arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class MinimumSwaps2 {
private static final Scanner SCANNER = new Scanner(System.in);
public static void main(String[] args) {
int length = SCANNER.nextInt();
int[] array = getArray(length);
System.out.println(minimumSwaps(array));
}
private static int[] getArray(int length) {
int[] array = new int[length];
for (int index = 0 ; index < array.length ; index++) {
array[index] = SCANNER.nextInt();
}
return array;
}
private static int minimumSwaps(int[] array) {
Map<Integer, Integer> elementIndices = getIndicesMap(array);
int swaps = 0;
for (int number = 1 ; number <= array.length ; number++) {
int index = elementIndices.get(number);
if (number == index + 1) {
continue;
}
swaps++;
array[index] = array[number - 1];
array[number - 1] = number;
elementIndices.put(number, number - 1);
elementIndices.put(array[index], index);
}
return swaps;
}
private static Map<Integer, Integer> getIndicesMap(int[] array) {
Map<Integer, Integer> result = new HashMap<>();
for (int index = 0 ; index < array.length ; index++) {
result.put(array[index], index);
}
return result;
}
}