排序算法之冒泡、插入和选择 - 黑马程序员技术交流社区

public class Sort {
public static void main(String[] args) {
//调用自定制方法生成int[]
int[] src=getIntegerArray(20);
for(int i:src){
System.out.print(i+" ");
}
System.out.println();
long startTime=System.nanoTime();
bubbleSort(src);
long endTime=System.nanoTime();
System.out.println("bubbleSort used time:"+(endTime-startTime));
long startTime1=System.nanoTime();
selectionSort(src);
long endTime1=System.nanoTime();
System.out.println("selectionsort used time:"+(endTime1-startTime1));
long startTime2=System.nanoTime();
insertionSort(src);
long endTime2=System.nanoTime();
System.out.println("insertionSort used time:"+(endTime2-startTime2));
//打印排序后数组
for(int i:src){
System.out.print(i+" ");
}
}
public static int[] bubbleSort(int[] src){
if(src==null||src.length==0)
return null;
int out,in;
for(out=src.length-1;out>0;out--){
for(in=0;in<out;in++){
if(src[in]>src[in+1]){
int temp=src[in];
src[in]=src[in+1];
src[in+1]=temp;
}
}
}
return src;
}
public static int[] selectionSort(int[] src){
if(src==null||src.length==0)
return null;
int out,in,min;
for(out=0;out<src.length-1;out++){
min=out;
for(in=out+1;in<src.length;in++){
if(src[in]<src[min]){
min=in;
}
int temp=src[out];
src[out]=src[min];
src[min]=temp;
}
}
return src;
}
public static int[] insertionSort(int[] src){//最快
if(src==null||src.length==0)
return null;
int out,in;
for(out=1;out<src.length;out++){
int temp=src[out];
in=out;
while(in>0&&src[in-1]>temp){
src[in]=src[in-1];
in--;
}
/* for (; in > 0; in--) { // 用时更少
if (src[in - 1] > temp) {
src[in] = src[in - 1];
} else {
break;
}
}*/
src[in]=temp;
}
return src;
}
//生成随机int[]供测试用
public static int[] getIntegerArray(int n){
if(n<=0)
return null;
int[] src=new int[n];
int index=0;
while(index<n){
src[index]=(int)(Math.random()*100);
index++;
}
return src;
}
}

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public class Sort {
/**
* main方法程序从这里启动
* @param args 从外部传入的参数列表
*/
public static void main(String[] args) {
//生成要排序的数组
int[] src = getIntegerArray(20);
//输出下要排序的数组
for(int i : src){
System.out.print(i + "\t");
}
System.out.println();
//冒泡排序
long startTime = System.nanoTime();
bubbleSort(src);
long endTime = System.nanoTime();
System.out.println("bubbleSort used time:" + (endTime - startTime));
//选择排序
long startTime1 = System.nanoTime();
selectionSort(src);
long endTime1 = System.nanoTime();
System.out.println("selectionsort used time:" + (endTime1 - startTime1));
//插入排序
long startTime2 = System.nanoTime();
insertionSort(src);
long endTime2 = System.nanoTime();
System.out.println("insertionSort used time:" + (endTime2 - startTime2));
//输出下排序后数组
for(int i : src){
System.out.print(i+"\t");
}
}
/**
* 冒泡排序
* @param src 要被排序的数字数组
* @return 排序后的数字数组
*/
public static int[] bubbleSort(int[] src) {
if(src == null || src.length == 0) {
return null;
}
int out, in;
for(out = src.length - 1; out > 0; out--) {
for(in = 0; in < out; in++) {
if(src[in] > src[in + 1]) {
int temp = src[in];
src[in] = src[in + 1];
src[in + 1] = temp;
}
}
}
return src;
}
/**
* 选择排序
* @param src 要被排序的数字数组
* @return 排序后的数字数组
*/
public static int[] selectionSort(int[] src) {
if(src == null || src.length == 0) {
return null;
}
int out, in, min;
for(out = 0; out < src.length - 1; out++) {
min = out;
for(in = out + 1; in < src.length; in++) {
if(src[in] < src[min]) {
min = in;
}
int temp = src[out];
src[out] = src[min];
src[min] = temp;
}
}
return src;
}
/**
* 插入排序
* @param src 要被排序的数字数组
* @return 排序后的数字数组
*/
public static int[] insertionSort(int[] src) { //最快
if(src == null || src.length == 0) {
return null;
}
int out,in;
for(out = 1; out < src.length; out++) {
int temp = src[out];
in = out;
while(in > 0 && src[in - 1] > temp) {
src[in] = src[in - 1];
in--;
}
/*
for (; in > 0; in--) { // 用时更少
if (src[in - 1] > temp) {
src[in] = src[in - 1];
} else {
break;
}
}
*/
src[in] = temp;
}
return src;
}
/**
* 随机生成一些整数并以数组形式返回, 供测试排序函数用
* @param n 要生成的整数数量
* @return 一些随机大小的整数的数组
*/
public static int[] getIntegerArray(int n) {
if(n <= 0) {
return null;
}
int[] src = new int[n];
int index = 0;
while(index < n){
src[index] = (int)(Math.random() * 100);
index++;
}
return src;
}
}

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