冒泡：
public class Sort {
public static void main(String[] args){
int[] values= {
3, 1, 6, 2, 9, 0, 7, 4, 5
};
sort(values);
for (int i =0; i < values.length; ++i) {
System.out.println("Index: " + i + "Value: " +values[i]);
}
}
public static void sort(int[] values){
inttemp;
for(int i =0; i < values.length; ++i) {
for (int j = 0; j < values.length - i - 1; ++j){
if (values[j] > values[j + 1]) {
temp = values[j];
values[j] = values[j + 1];
values[j + 1] = temp;
}
}
}
}
}
快速排序
public class QuickSort {
public static void swap(int a[], int i, int j){
if (i == j){
return;
}
int tmp =a[i];
a[i] =a[j];
a[j] =tmp;
}
public static int partition(int array[], intlow, int high) {
//当前位置为第一个元素所在位置
int p_pos =low;
//采用第一个元素为轴
int pivot =array[p_pos];
for (int i =low + 1; i <= high; i++) {
if (array[i] < pivot) {
p_pos++;
swap(array, p_pos, i);
for (int m = 0; m < array.length; ++m) {
System.out.println("Index: " + m + "Value: " + array[m]);
}
}
}
swap(array,low, p_pos);
returnp_pos;
}
public static void quickSort(int array[], intlow, int high) {
if (low< high) {
int pivot = partition(array, low, high);
quickSort(array, low, pivot - 1);
quickSort(array, pivot + 1, high);
}
}
public static void main(String[] args){
QuickSortquicksort = new QuickSort();
int[] values= {
3, 1, 6, 2, 9, 0, 7, 4, 5};
quicksort.quickSort(values, 0, 8);
for (int i =0; i < values.length; ++i) {
System.out.println("Index: " + i + "Value: " +values[i]);
}
}
}
福利送另两个算法：
java选择排序和二分查找
package cn.com.exception;
public class Search
{
public static void main(String[] args)
{
int[] arr ={1,3,4,56,34,22,35,87,23};
Search.searchSort(arr);
for(int e: arr){
System.out.print(e + " ");
}
System.out.println();
int index =Search.binarySearch(arr, 22);
System.out.println(index);
}
// 选择排序(主要是用K记录位置避免多次交换)
public static void searchSort(int[] a){
int temp, k;
for(int i = 0; i< a.length; i++){
k = i;
for(int j =k + 1; j < a.length; j++){
if(a[j] < a[k]){
k = j;
}
}
if(k !=i){
temp = a[i];
a[i] = a[k];
a[k] = temp;
}
}
}
// 二分法查找(每次折半根据与中间位置的对比向左向右继续折半)
public static int binarySearch(int[] a, int num){
if(a.length == 0) return-1;
int startPos = 0;
int endPos = a.length -1;
int m = (startPos + endPos) /2;
while(startPos<= endPos){
if(num ==a[m]) return m;
if(num> a[m]){
startPos = m + 1;
}
if(num< a[m]){
endPos = m - 1;
}
m =(startPos + endPos) /2;
}
returnm;
}
}
