java排序

java排序

package com.test.yjw;

public class Sort {

 //冒泡
 /**
  *
  */
 public static void bubbleSort(int a[]) {
  int len = a.length;
  for (int i = 0; i < len - 1; i++) {
   for (int j = 0; j < len - 1 - i; j++) {
    if (a[j] > a[j + 1]) {
    int temp = a[j];
    a[j] = a[j + 1];
    a[j + 1] = temp;
    }
   }
  }
  for(int t : a){
   System.out.println(t);
  }
 }
 //选择排序
 public static void selectSort(int a[]) {
  int temp = 0;
  int len = a.length;
  for (int i = 0; i < len - 1; i++) {
   int min = a[i];
   int index = i;
   for (int j = i + 1; j < len; j++) {
    if (min > a[j]) {
     min = a[j];
     index = j;
    }
   }
   temp = a[i];
   a[i] = a[index];
   a[index] = temp;
  }
  for(int t : a){
   System.out.println(t);
  }
 }
// 插入排序{9,5,1,3,7,8,6,2,0,4}
 public static void insertSort(int a[]) {
  int len = a.length;
  for (int i = 1; i < len; i++) {
   int temp = a[i];// 待插入的值
   int index = i;// 待插入的位置
   while (index > 0 && a[index - 1] > temp) {
    a[index] = a[index - 1];// 待插入的位置重新赋更大的值
    index--;// 位置往前移
   }
   a[index] = temp;
  }
  for(int t : a){
   System.out.println(t);
  }
 }
 //快速排序
 public static void quickSort(int a[], int low, int height) {
  if (low < height) {
   int result = partition(a, low, height);
   quickSort(a, low, result - 1);
   quickSort(a, result + 1, height);
  }
  
 }
 public static int partition(int a[], int low, int height) {
  int key = a[low];
  while (low < height) {
   while (low < height && a[height] >= key)
   height--;
   a[low] = a[height];
   while (low < height && a[low] <= key)
   low++;
   a[height] = a[low];
  }
  a[low] = key;
  return low;
 }
  public static void swap(int a[], int i, int j) {              // 通过临时变量,交换数据
      int tmp = a[i];
      a[i] = a[j];
      a[j] = tmp;
    }                                                                  // 第一次交换分析
    public static void quicksort(int a[], int low, int high) {   // 假设传入low=0; high=a.length-1;
      if (low < high) {                                          // 条件判断
       int pivot, p_pos, i;                                    // 声明变量
          p_pos = low;                                         // p_pos指向low,即位索引为0位置 ;
          pivot = a[p_pos];                                   // 将0位置上的数值赋给pivot;
          for (i = low + 1; i <= high; i++) {             // 循环次数, i=1;
           if (a[i]>pivot) {                                      // 1位置的数与0位置数作比较: a[1]>a[0]
             p_pos++;                                           // 2位与1位比较,3位与2位比较......
             swap(a, p_pos, i);                              // 传参并调用swap    
            }
          }
        swap(a, low, p_pos);                              // 将p_pos设为high再次调用swap
        quicksort(a, low, p_pos - 1);                  // 递归调用,排序左半区
        quicksort(a, p_pos + 1, high);                // 递归调用,排序右半区
      }
    
    }
  
 public static void main(String[] args) {
  int[] a =new  int[]{9,5,1,3,7,8,6,2,0,4};
  //Sort.bubbleSort(a);
  //Sort.selectSort(a);
  //Sort.insertSort(a);
  Sort.quickSort(a, 0, a.length-1);
   for(int t : a){
    System.out.println(t);
   }
 }
}