sortedArrDistanceLessK() 已知一个几乎有序的数组。几乎有序是指，如果把数组排好顺序的话，每个元素移动的距离一定不超过k，并且k相对于数组长度来说是比较小的。 请选择一个合适的排

package class06;

import java.util.Arrays;
import java.util.PriorityQueue;

/**
 * sortedArrDistanceLessK()
 * 已知一个几乎有序的数组。几乎有序是指，如果把数组排好顺序的话，每个元素移动的距离一定不超过k，并且k相对于数组长度来说是比较小的。
 * 请选择一个合适的排序策略，对这个数组进行排序。
 */
public class Code04_SortArrDistanceLessK {
    public static void sortedArrDistanceLessK(int[] arr, int k) {
//        arr = new int[]{2, 1, 8, 4, 9, 3, 5};
        if (k == 0) {
            return;
        }
        PriorityQueue<Integer> heap = new PriorityQueue<>();
        int index = 0;
        for (; index <= Math.min(arr.length - 1, k - 1); index++) {//=号不能少，如果不写=号，会导致排序错误。
            heap.add(arr[index]);
        }
        int i = 0;
        for (; index < arr.length; i++, index++) {
            heap.add(arr[index]);
            arr[i] = heap.poll();
        }
        while (!heap.isEmpty()) {
            arr[i++] = heap.poll();
        }
    }

    public static void sortedArrDistanceLessK111(int[] arr, int k) {
        if (k == 0) {
            return;
        }
        // 默认小根堆
        PriorityQueue<Integer> heap = new PriorityQueue<>();
        int index = 0;
        // 0...K-1
        for (; index <= Math.min(arr.length - 1, k - 1); index++) {
            heap.add(arr[index]);
        }
        int i = 0;
        for (; index < arr.length; i++, index++) {
            heap.add(arr[index]);
            arr[i] = heap.poll();
        }
        while (!heap.isEmpty()) {
            arr[i++] = heap.poll();
        }
    }

    public static int[] randomArrayNoMoveMoreK(int maxSize, int maxValue, int K) {
        int[] arr = new int[(int) (Math.random() * (maxSize + 1))];
        for (int i = 0; i < arr.length; i++) {
            arr[i] = (int) (Math.random() * maxValue);
        }
        Arrays.sort(arr);
        boolean[] isSwapped = new boolean[arr.length];
        for (int i = 0; i < arr.length; i++) {
//            int j = (int) (Math.random() * (Math.min(arr.length - 1, K - 1)));
            int j = Math.min(i + (int) (Math.random() * (K + 1)), arr.length - 1);
            if (!isSwapped[i] && !isSwapped[j]) {
                isSwapped[i] = true;
                isSwapped[j] = true;
                swap(arr, i, j);
            }
        }
        return arr;
    }

    public static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }

    public static int[] copyArray(int[] arr) {
        if (arr == null) {
            return null;
        }
        int[] res = new int[arr.length];
        for (int i = 0; i < arr.length; i++) {
            res[i] = arr[i];
        }
        return res;
    }

    // for test
    public static boolean isEqual(int[] arr1, int[] arr2) {
        if ((arr1 == null && arr2 != null) || (arr1 != null && arr2 == null)) {
            return false;
        }
        if (arr1 == null && arr2 == null) {
            return true;
        }
        if (arr1.length != arr2.length) {
            return false;
        }
        for (int i = 0; i < arr1.length; i++) {
            if (arr1[i] != arr2[i]) {
                return false;
            }
        }
        return true;
    }

    // for test
    public static void printArray(int[] arr) {
        if (arr == null) {
            return;
        }
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    public static void main(String[] args) {
        int maxSize = 100;
        int maxValue = 100;
        int testTimes = 100000;
        System.out.println("test start!");
        for (int i = 0; i < testTimes; i++) {
            int k = (int) (Math.random() * maxSize) + 1;
            //int k = 3;
            int[] arr0 = randomArrayNoMoveMoreK(maxSize, maxValue, k);
            int[] arr1 = copyArray(arr0);
            int[] arr2 = copyArray(arr0);
            sortedArrDistanceLessK(arr1, k);
            Arrays.sort(arr2);
            if (!isEqual(arr1, arr2)) {
                System.out.println("oops!");
                System.out.println("k = " + k);
                System.out.println("arr0 = " + Arrays.toString(arr0));
                System.out.println("arr1 = " + Arrays.toString(arr1));
                System.out.println("arr2 = " + Arrays.toString(arr2));
                break;
            }
        }
        System.out.println("test end!");
    }

}