import java.util.Arrays;
public class SortDemo {
private static long[] arr = {6,5,2,7,1,8,4,3};
// private static long[] arr = {1,2,3,4,5,6,7,8};
private static int count = 0;
/**
* 冒泡排序
* O(n2)
*/
public static void bubble(){
long temp = Long.MIN_VALUE;
int len = arr.length;
for(int j = 0;j<len;j++){
for(int i = 0;i<len-1;i++){
if(arr[i]>arr[i+1]){
temp = arr[i+1];
arr[i+1] = arr[i];
arr[i] = temp;
}
}
}
}
/**
* 选择排序
* O(n2)
*/
public static void select(){
int len = arr.length;
long temp = Long.MIN_VALUE;
int index = 0;
for(int j = 0;j<len;j++){
index = j;
for(int i = j;i<len;i++){
if(arr[i]<arr[index]){
index = i;
}
}
temp = arr[j];
arr[j] = arr[index];
arr[index] = temp;
print();
}
}
/**
* 插入排序
* O(n2)
*/
public static void insert(){
int len = arr.length;
long temp;
for(int i=1;i<len;i++){
int j = i-1;
temp = arr[i];
while(j>=0 && temp<arr[j]){
arr[j+1] = arr[j];
j--;
}
arr[j+1] = temp;
print();
}
}
/**
* 快速排序
* O(N*longN)
*/
public static void quick(){
quick(arr,0,arr.length-1);
print();
}
private static long[] quick(long[] a,int lo,int hi){
if(hi<lo)return a;
long temp = 0;
int index = lo;
for(int i = lo;i<hi;i++){
if(a[i]<a[hi]){
temp = a[i];
a[i] = a[index];
a[index++] = temp;
}
}
temp = a[hi];
a[hi] = a[index];
a[index] = temp;
if(index==lo)return a;
quick(a,lo,index-1);
quick(a,index+1,hi);
return a;
}
/**
* 归并排序
* O(N*longN)
*/
public static void merge (){
merge(arr,0,arr.length-1);
print();
}
public static void merge(long[] a,int lo,int hi){
int mid = lo +(hi-lo)/2;
if(lo < hi){
merge(a,lo,mid);
merge(a,mid+1,hi);
merge(a,lo,mid,hi);
}
}
public static void merge(long[] a,int lo,int mid,int hi){
long[] temp = new long[hi-lo+1];
int i=lo,j=mid+1,index=0;
while(i<=mid&&j<=hi){
if(a[i]>a[j]){
temp[index++] = a[j++];
}else{
temp[index++] = a[i++];
}
}
while(i<=mid){
temp[index++] = a[i++];
}
while(j<=hi){
temp[index++] = a[j++];
}
System.arraycopy(temp, 0, a, lo, temp.length);
}
public static void print(){
System.out.println(Arrays.toString(arr));
}
public static void main(String[] args) {
merge();
}
}
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