[Java知识库]算法 —— 冒泡排序

冒泡排序

冒泡排序是比较两个相邻元素，如果它们不符合预期的顺序就交换的一个排序过程。

冒泡排序就像水中气泡上升到水面的运动一样，数组的每个元素在每次迭代中都把当前迭中最大(或最小)的元素移动到最后，因此被称为冒泡排序。

冒泡排序的工作流程

1.第一次迭代（比较和交换）

2.后续的迭代过程

代码实现

Swift实现

import Foundation


func bubbleSort(array:inout Array<Int>) {
    //遍历数组的每个元素,让每个元素都走一遍冒泡流程
    for i in 0 ..< array.count - 1 {
        //第i个元素走冒泡流程，因为i前面的元素走过冒泡交换流程后，就都已经有序的浮到尾(顶)部了，所以越遍历到后面需要冒泡的层次就会越少
        for j in 0 ..< array.count - 1 - i {
            //冒泡过程：比较大小，并交换，把大的元素交换到后面
            if array[j] > array[j + 1] {
                array.swapAt(j, j+1)
            }
        }
    }
}

//打印
func printBubbleSort(_ array:inout [Int]){
    bubbleSort(array: &array)
    print(array)
}

var arr:[Int] = [3, 2, 5, 7, 1, 5, 4, 8, 11, 0]
printBubbleSort(&arr);

Python实现

# Bubble sort in Python

def bubbleSort(array):
    
  # loop to access each array element
  for i in range(len(array)):

    # loop to compare array elements
    for j in range(0, len(array) - i - 1):

      # compare two adjacent elements
      # change > to < to sort in descending order
      if array[j] > array[j + 1]:

        # swapping elements if elements
        # are not in the intended order
        temp = array[j]
        array[j] = array[j+1]
        array[j+1] = temp


data = [-2, 45, 0, 11, -9]

bubbleSort(data)

print('Sorted Array in Ascending Order:')
print(data)

Java的实现

// Bubble sort in Java

import java.util.Arrays;

class Main {

  // perform the bubble sort
  static void bubbleSort(int array[]) {
    int size = array.length;
    
    // loop to access each array element
    for (int i = 0; i < size - 1; i++)
    
      // loop to compare array elements
      for (int j = 0; j < size - i - 1; j++)

        // compare two adjacent elements
        // change > to < to sort in descending order
        if (array[j] > array[j + 1]) {

          // swapping occurs if elements
          // are not in the intended order
          int temp = array[j];
          array[j] = array[j + 1];
          array[j + 1] = temp;
        }
  }

  public static void main(String args[]) {
      
    int[] data = { -2, 45, 0, 11, -9 };
    
    // call method using class name
    Main.bubbleSort(data);
    
    System.out.println("Sorted Array in Ascending Order:");
    System.out.println(Arrays.toString(data));
  }
}

C实现

// Bubble sort in C

#include <stdio.h>

// perform the bubble sort
void bubbleSort(int array[], int size) {

  // loop to access each array element
  for (int step = 0; step < size - 1; ++step) {
      
    // loop to compare array elements
    for (int i = 0; i < size - step - 1; ++i) {
      
      // compare two adjacent elements
      // change > to < to sort in descending order
      if (array[i] > array[i + 1]) {
        
        // swapping occurs if elements
        // are not in the intended order
        int temp = array[i];
        array[i] = array[i + 1];
        array[i + 1] = temp;
      }
    }
  }
}

// print array
void printArray(int array[], int size) {
  for (int i = 0; i < size; ++i) {
    printf("%d  ", array[i]);
  }
  printf("\n");
}

int main() {
  int data[] = {-2, 45, 0, 11, -9};
  
  // find the array's length
  int size = sizeof(data) / sizeof(data[0]);

  bubbleSort(data, size);
  
  printf("Sorted Array in Ascending Order:\n");
  printArray(data, size);
}

C++实现

// Bubble sort in C++

#include <iostream>
using namespace std;

// perform bubble sort
void bubbleSort(int array[], int size) {

  // loop to access each array element
  for (int step = 0; step < (size-1); ++step) {
      
    // loop to compare array elements
    for (int i = 0; i < size - (step-1); ++i) {

      // compare two adjacent elements
      // change > to < to sort in descending order
      if (array[i] > array[i + 1]) {

        // swapping elements if elements
        // are not in the intended order
        int temp = array[i];
        array[i] = array[i + 1];
        array[i + 1] = temp;
      }
    }
  }
}

// print array
void printArray(int array[], int size) {
  for (int i = 0; i < size; ++i) {
    cout << "  " << array[i];
  }
  cout << "\n";
}

int main() {
  int data[] = {-2, 45, 0, 11, -9};
  
  // find array's length
  int size = sizeof(data) / sizeof(data[0]);
  
  bubbleSort(data, size);
  
  cout << "Sorted Array in Ascending Order:\n";  
  printArray(data, size);
}