堆的实现
`package mergeSort;
import java.util.Comparator; import java.util.PriorityQueue; public class Heap {
public static class MyMaxHeap{
private int[] heap;
private final int limit;
private int heapSize;
public MyMaxHeap(int limit) {
heap= new int[limit];
this.limit=limit;
heapSize=0;
}
public boolean isEmpty() {
return heapSize==0;
}
public boolean isFull() {
return heapSize==limit;
}
public void push(int value) {
if(heapSize==limit) {
throw new RuntimeException("heap is full");
}
heap[heapSize]=value;
heapInsert(heap, heapSize++);
}
public int pop() {
int ans=heap[0];
swap(heap,0,--heapSize);
heapify(heap,0,heapSize);
return ans;
}
private void heapInsert(int[] arr,int index) {
while(index>(index-1)/2) {
swap(heap,index,(index-1)/2);
index=(index-1)/2;
}
}
private void heapify(int[] arr,int index,int heapSize) {
int left=index*2+1;
while(left<heapSize) {
int largest=left+1<heapSize && arr[left+1]>arr[left]?left+1:left;
largest=arr[largest]>arr[index]?largest:index;
if(largest==index) {
break;
}
swap(arr,largest,index);
index=largest;
left=index*2+1;
}
}
private void swap(int[] arr,int i,int j) {
int tmp=arr[i];
arr[i]=arr[j];
arr[j]=tmp;
}
}
public static class RightMaxHeap {
private int[] arr;
private final int limit;
private int size;
public RightMaxHeap(int limit) {
arr = new int[limit];
this.limit = limit;
size = 0;
}
public boolean isEmpty() {
return size == 0;
}
public boolean isFull() {
return size == limit;
}
public void push(int value) {
if (size == limit) {
throw new RuntimeException("heap is full");
}
arr[size++] = value;
}
public int pop() {
int maxIndex = 0;
for (int i = 1; i < size; i++) {
if (arr[i] > arr[maxIndex]) {
maxIndex = i;
}
}
int ans = arr[maxIndex];
arr[maxIndex] = arr[--size];
return ans;
}
}
public static class MyComparator implements Comparator<Integer>{
@Override
public int compare(Integer o1, Integer o2) {
return o2 - o1;
}
}
public static void main(String[] args) {
// 小根堆
// PriorityQueue heap = new PriorityQueue<>(new MyComparator()); // heap.add(5); // heap.add(5); // heap.add(5); // heap.add(3); // // 5 , 3 // System.out.println(heap.peek()); // heap.add(7); // heap.add(0); // heap.add(7); // heap.add(0); // heap.add(7); // heap.add(0); // System.out.println(heap.peek()); // while(!heap.isEmpty()) { // System.out.println(heap.poll()); // }
int value = 1000;
int limit = 100;
int testTimes = 1000000;
for (int i = 0; i < testTimes; i++) {
int curLimit = (int) (Math.random() * limit) + 1;
MyMaxHeap my = new MyMaxHeap(curLimit);
RightMaxHeap test = new RightMaxHeap(curLimit);
int curOpTimes = (int) (Math.random() * limit);
for (int j = 0; j < curOpTimes; j++) {
if (my.isEmpty() != test.isEmpty()) {
System.out.println("Oops!");
}
if (my.isFull() != test.isFull()) {
System.out.println("Oops!");
}
if (my.isEmpty()) {
int curValue = (int) (Math.random() * value);
my.push(curValue);
test.push(curValue);
} else if (my.isFull()) {
if (my.pop() != test.pop()) {
System.out.println("Oops!");
}
} else {
if (Math.random() < 0.5) {
int curValue = (int) (Math.random() * value);
my.push(curValue);
test.push(curValue);
} else {
if (my.pop() != test.pop()) {
System.out.println("Oops!");
}
}
}
}
}
System.out.println("finish!");
}
} `
堆排序
`package mergeSort;
import java.util.Arrays; import java.util.PriorityQueue;
public class c1_HeapSort {
public static void heapSort(int[] arr) {
if(arr==null || arr.length<2) {
return;
}
for(int i=arr.length-1;i>=0;i--) {
heapify(arr,i,arr.length);
}
int heapSize=arr.length;
swap(arr,0,--heapSize);
while(heapSize>0) {
heapify(arr,0,heapSize);
swap(arr,0,--heapSize);
}
}
public static void heapInsert(int[] arr,int index) {
while(arr[index]>arr[(index-1)/2]) {
swap(arr,index,(index-1)/2);
index=(index-1)/2;
}
}
public static void heapify(int[] arr,int index,int heapSize) {
int left=index*2+1;
while(left<heapSize) {
int largest=left+1<heapSize && arr[left+1]>arr[left]?left+1:left;
largest=arr[index]>arr[largest]?index:largest;
if(largest==index) {
break;
}
swap(arr,largest,index);
index=largest;
left=index*2+1;
}
}
public static void swap(int[] arr, int i, int j) {
int tmp = arr[i];
arr[i] = arr[j];
arr[j] = tmp;
}
// for test
public static void comparator(int[] arr) {
Arrays.sort(arr);
}
// for test
public static int[] generateRandomArray(int maxSize, int maxValue) {
int[] arr = new int[(int) ((maxSize + 1) * Math.random())];
for (int i = 0; i < arr.length; i++) {
arr[i] = (int) ((maxValue + 1) * Math.random()) - (int) (maxValue * Math.random());
}
return arr;
}
// for test
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();
}
// for test
public static void main(String[] args) {
// 默认小根堆
PriorityQueue<Integer> heap = new PriorityQueue<>();
heap.add(6);
heap.add(8);
heap.add(0);
heap.add(2);
heap.add(9);
heap.add(1);
while (!heap.isEmpty()) {
System.out.println(heap.poll());
}
int testTime = 500000;
int maxSize = 100;
int maxValue = 100;
boolean succeed = true;
for (int i = 0; i < testTime; i++) {
int[] arr1 = generateRandomArray(maxSize, maxValue);
int[] arr2 = copyArray(arr1);
heapSort(arr1);
comparator(arr2);
if (!isEqual(arr1, arr2)) {
succeed = false;
break;
}
}
System.out.println(succeed ? "Nice!" : "Fucking fucked!");
int[] arr = generateRandomArray(maxSize, maxValue);
int[] array = copyArray(arr);
printArray(arr);
heapSort(arr);
comparator(array);
printArray(arr);
printArray(array);
}
}`
排序（位置变动不会超过k个）
`package mergeSort;
import java.util.Arrays; import java.util.PriorityQueue;
public class SortArrayDistanceLessK {
public static void sortedArrDistanceLessK(int[] arr, int k) {
if(k==0) {
return;
}
PriorityQueue<Integer> heap=new PriorityQueue<>();
int index=0;
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();
}
}
// for test
public static void comparator(int[] arr, int k) {
Arrays.sort(arr);
}
// for test
public static int[] randomArrayNoMoveMoreK(int maxSize, int maxValue, int K) {
int[] arr = new int[(int) ((maxSize + 1) * Math.random())];
for (int i = 0; i < arr.length; i++) {
arr[i] = (int) ((maxValue + 1) * Math.random()) - (int) (maxValue * Math.random());
}
// 先排个序
Arrays.sort(arr);
// 然后开始随意交换，但是保证每个数距离不超过K
// swap[i] == true, 表示i位置已经参与过交换
// swap[i] == false, 表示i位置没有参与过交换
boolean[] isSwap = new boolean[arr.length];
for (int i = 0; i < arr.length; i++) {
int j = Math.min(i + (int) (Math.random() * (K + 1)), arr.length - 1);
if (!isSwap[i] && !isSwap[j]) {
isSwap[i] = true;
isSwap[j] = true;
int tmp = arr[i];
arr[i] = arr[j];
arr[j] = tmp;
}
}
return arr;
}
// for test
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();
}
// for test
public static void main(String[] args) {
System.out.println("test begin");
int testTime = 500000;
int maxSize = 100;
int maxValue = 100;
boolean succeed = true;
for (int i = 0; i < testTime; i++) {
int k = (int) (Math.random() * maxSize) + 1;
int[] arr = randomArrayNoMoveMoreK(maxSize, maxValue, k);
int[] arr1 = copyArray(arr);
int[] arr2 = copyArray(arr);
sortedArrDistanceLessK(arr1, k);
comparator(arr2, k);
if (!isEqual(arr1, arr2)) {
succeed = false;
System.out.println("K : " + k);
printArray(arr);
printArray(arr1);
printArray(arr2);
break;
}
}
System.out.println(succeed ? "Nice!" : "Fucking fucked!");
}
} `
