算法设计与分析基础-6.4、堆和堆排序

堆排序递归实现，用java，最后两个函数是为了输出好看
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class BuildMaxHeap {
private static int[] sort= new int[] { 3, 4, 43, 5, 1, 6, 23, 55, 12, 6 };

public static void main(String[] args) {
// for (int i = 0; i < 10; i++) {
// Scanner scanner = new Scanner(System.in);
// sort[i] = scanner.nextInt();
// }
print(sort);
buildMaxHeap(sort);
print(sort);
heapSort(sort);
print(sort);
}

private static int getParent(int i) {
return (i - 1) >> 1;

}

private static int getLeftChild(int i) {
return (i << 1) + 1;

}

private static int getRightChild(int i) {
return (i << 1) + 2;
}

private static void buildMaxHeap(int[] data) {
int length = data.length;
int startIndex = length / 2 - 1;
for (int i = startIndex; i >= 0; i--)
maxHeap(data, length, i);
}

private static void maxHeap(int[] data, int heapSize, int index) {
int left = getLeftChild(index);
int right = getRightChild(index);
int largest = index;
if (left < heapSize && data[left] > data[index])
largest = left;
if (right < heapSize && data[right] > data[largest])   //编写的时候这块除了问题，不要把边界、还有变量变化搞混了！！！
largest = right;
if (largest != index) {
int tmp = data[index];
data[index] = data[largest];
data[largest] = tmp;
maxHeap(data, heapSize, largest);
}
}

private static void heapSort(int[] data)
{
for(int i=data.length-1;i>=0;i--)
{
int tmp=data[0];
data[0]=data[i];
data[i]=tmp;
maxHeap(data, i, 0);
}
}
private static void print(int[] data){
int pre = -2;
for (int i = 0; i < data.length; i++) {
if (pre < (int)getLog(i+1)) {
pre = (int)getLog(i+1);
System.out.println();
}
System.out.print(data[i] + " |");
}
}

/**
* 以2为底的对数
* @param param
* @return
*/
private static double getLog(double param){
return Math.log(param)/Math.log(2);
}
}

//还是最大堆，加入了插入元素，这时候用数组表示就不合适，改用List，这样，堆的长度可以动态变换
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.Set;

import javax.swing.text.ChangedCharSetException;
import javax.xml.crypto.Data;

public class BuildMaxHeap {
// private static int[] sort= new int[] { 3, 4, 43, 5, 1, 6, 23, 55, 12, 6 };
private static List<Integer> sort=new ArrayList<Integer>();

public static void main(String[] args) {
sort.add(3);
sort.add(4);
sort.add(43);
sort.add(5);
sort.add(1);
sort.add(6);
sort.add(23);
sort.add(55);
sort.add(12);
sort.add(6);

// for (int i = 0; i < 10; i++) {
// Scanner scanner = new Scanner(System.in);
// sort[i] = scanner.nextInt();
// }
print(sort);
buildMaxHeap(sort);
//print(sort);
//heapSort(sort);
print(sort);
insert(sort, 19);
print(sort);
heapSort(sort);
print(sort);
}

private static int getParent(int i) {
return (i - 1) >> 1;

}

private static int getLeftChild(int i) {
return (i << 1) + 1;

}

private static int getRightChild(int i) {
return (i << 1) + 2;

}

private static void buildMaxHeap(List<Integer> data) {
int length = data.size();
int startIndex = length / 2 - 1;
for (int i = startIndex; i >= 0; i--)
maxHeap(data, length, i);

}

private static void maxHeap(List<Integer> data, int heapSize, int index) {
int left = getLeftChild(index);
int right = getRightChild(index);
int largest = index;
if (left < heapSize && data.get(left) > data.get(index))
largest = left;
if (right < heapSize && data.get(right) > data.get(largest))
largest = right;
if (largest != index) {
int tmp = data.get(index);
data.set(index, data.get(largest));
data.set(largest, tmp);
maxHeap(data, heapSize, largest);
}
}

private static void heapSort(List<Integer> data)
{
for(int i=data.size()-1;i>=0;i--)
{
int tmp=data.get(0);
data.set(0, data.get(i));
data.set(i, tmp);
maxHeap(data, i, 0);
}
}

private static void insert(List<Integer> data,int v)
{
int last=data.size();
data.add(v);
int i;
int tmp;
int parent;
for(i=last;i>=0;i=parent)
{
parent = (i-1)/2;
if(parent>=0&&data.get(i)>data.get(parent))    //注意parent的值  (-1)>>1=-1   -1/2=0
{
tmp=data.get(i);
data.set(i, data.get(parent));
data.set(parent, tmp);
}
else {
break;
}
}
}

private static void print(List<Integer> data){
int pre = -2;
for (int i = 0; i < data.size(); i++) {
if (pre < (int)getLog(i+1)) {
pre = (int)getLog(i+1);
System.out.println();
}
System.out.print(data.get(i) + " |");
}
}

/**
* 以2为底的对数
* @param param
* @return
*/
private static double getLog(double param){
return Math.log(param)/Math.log(2);
}
}