import java.util.*;
class SortUtilityTools{
public static void main(String[] args){
int[] arr = {3,5,13,8,4,2,1,20,19,14,17};
SortUtilityTools.HeapSort(arr);
for(int a:arr){
System.out.println(a);
}
int a1 = SortUtilityTools.binarySearch(arr,13);
System.out.println(a1);
}
//冒泡排序,从小到大
public static int[] BubbleSort(int[] arr){
//边界检查
if(arr == null) return null;
//BubbleSort
int length = arr.length;
int temp;
for(int i = 0;i < length;++i){
for(int j = 0;j < length-(i+1);++j){
if(arr[j] > arr[j+1]){
temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
}
}
}
return arr;
}
//选择排序
public static int[] SelectSort(int[] arr){
//边界检查
if(arr == null) return null;
//SelectSort
int length = arr.length;
int min = Integer.MAX_VALUE;
int temp = 0;
int tempNum;
for(int i = 0;i < length;++i){
for(int j = i;j < length;++j){
if(arr[j] < min){
min = arr[j];
temp = j;
}
}
tempNum = arr[temp];
arr[temp] = arr[i];
arr[i] = tempNum;
min = Integer.MAX_VALUE;
}
return arr;
}
//插入排序
public static int[] InsertSort(int[] arr){
//边界检查
if(arr == null) return null;
//InsertSort
int length = arr.length;
int temp;
for(int i = 0; i < length;++i){
for(int j = i;j > 0;j--){
if(arr[j] < arr[j-1]){
temp = arr[j];
arr[j] = arr[j-1];
arr[j-1] = temp;
}else if(arr[j] > arr[j-1]){
break;
}
}
}
return arr;
}
//归并排序,递归版本,第二遍
public static void MergeSort(int[] arr,int l,int r){
//边界处理
if(arr == null) return;
//MergeSort
if(l < r){
int m = (l+r) >> 1;
MergeSort(arr,l,m);
MergeSort(arr,m+1,r);
Merge(arr,l,m,r);
}
}
private static void Merge(int[] arr,int l,int m,int r){
//L and R
int[] L = new int[m-l+2];
int[] R = new int[r-m+1];
int i,j;
for(i = 0;i < L.length-1;++i){
L[i] = arr[l+i];
}
L[i] = Integer.MAX_VALUE;
i = 0;
for(j = 0;j < R.length-1;++j){
R[j] = arr[m+1+j];
}
R[j] = Integer.MAX_VALUE;
j = 0;
//compare L and R
while(l <= r){
if(L[i] <= R[j]){
arr[l++] = L[i++];
}else{
arr[l++] = R[j++];
}
}
}
//快速排序,第二遍
public static void Quick(int[] arr,int l,int r){
//边界检查
if(arr == null) return;
int x;
if(l < r){
x = R_Quick(arr,l,r);
Quick(arr,l,x-1);
Quick(arr,x+1,r);
}
}
private static int QuickSort(int[] arr,int l,int r){
//i and j
int i = l - 1;
int j;
//pivot
int p = arr[r];
int temp;
for(j = l;j < r;++j){
if(arr[j] < p){
i++;
temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}
temp = arr[i+1];
arr[i+1] = arr[r];
arr[r] = temp;
return i+1;
}
//R-Quick
public static int R_Quick(int[] arr,int l,int r){
int temp;
Random random = new Random();
int i = random.nextInt(r-l) + l;
temp = arr[r];
arr[r] = arr[i];
arr[i] = temp;
return QuickSort(arr,l,r);
}
//建堆
private static int BuildMaxHeap(int[] arr){
int heapSize = arr.length;
int length = arr.length;
for(int i = length >> 1;i >= 0;i--){
Max_Heapify(arr,i,heapSize);
}
return heapSize;
}
private static void Max_Heapify(int[] arr,int i,int heapSize){
//判断左右孩子是否符合最大堆性质
int l = (i << 1) + 1;
int r = (i << 1) + 2;
int largest = i;
int temp;
if(l < heapSize && arr[l] > arr[i]){
largest = l;
}
if(r < heapSize && arr[r] > arr[largest]){
largest = r;
}
if(largest != i){
temp = arr[largest];
arr[largest] = arr[i];
arr[i] = temp;
Max_Heapify(arr,largest,heapSize);
}
}
//堆排序
public static void HeapSort(int[] arr){
if(arr == null) return;
int heapSize = BuildMaxHeap(arr);
int temp;
while(heapSize > 1){
temp = arr[0];
arr[0] = arr[heapSize-1];
arr[heapSize-1] = temp;
heapSize--;
Max_Heapify(arr,0,heapSize);
}
}
//Array的二分查找,返回-1代表没有找到
public static int binarySearch(int[] arr,int target){
//边界检查
if(arr == null) return -1;
//折半查找
int length = arr.length;
int left = 0;
int right = length - 1;
int mid;
int midNum;
while(length >= 1 && left <= right){
mid = (left + right) >> 1;
midNum = arr[mid];
if(target == midNum){
return mid;
}else if(target < arr[mid]){
right = mid - 1;
}else{
left = mid + 1;
}
}
return -1;
}
}
各类排序
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