使用 Java 的 DSA - 冒泡排序
概述
冒泡排序是一种简单的排序算法。此排序算法是基于比较的算法,其中比较每对相邻元素,如果元素顺序不正确,则交换元素。此算法不适用于大型数据集,因为其平均和最坏情况复杂度为 O(n2),其中 n 为项目数。
伪代码
procedure bubbleSort( A : array of items ) for i = 1 to length(A) - 1 inclusive do: swapped = false for j = 1 to length(A) - 1 inclusive do: /* 比较相邻元素 */ if A[i-1] > A[i] then /* 交换它们 */ swap( A[i-1], A[i] ) swapped = true end if end for /*如果没有交换数字,则意味着 数组现在已排序,打破循环。*/ if(!swapped) then break end for end procedure
演示程序
package com.tutorialspoint.simplesort; import java.util.Arrays; public class BubbleSortDemo { public static void main(String[] args){ int[] sourceArray = {4,6,3,2,1,9,7}; System.out.println("Input Array: " + Arrays.toString(sourceArray)); printline(50); System.out.println("Output Array: " + Arrays.toString(bubbleSort(sourceArray))); printline(50); } public static void printline(int count){ for(int i=0;i <count-1;i++){ System.out.print("="); } System.out.println("="); } public static int[] bubbleSort(int[] intArray){ int temp; boolean swapped = false; // 循环遍历所有数字 for(int i=0; i < intArray.length-1; i++){ swapped = false; // 循环遍历前面的数字 for(int j=1; j < intArray.length-i; j++){ System.out.println(" Items compared: [ " + intArray[j-1] + ", " + intArray[j] +" ]" ); // 检查下一个数字是否小于当前数字 // 交换数字。 //(将最高的数字向上冒泡) if(intArray[j-1] > intArray[j]){ temp=intArray[j-1]; intArray[j-1] = intArray[j]; intArray[j] = temp; swapped = true; } } // 如果没有交换数字,则意味着 // 数组现在已排序,打破循环。 if(!swapped){ break; } System.out.println("Iteration "+(i+1) +"#: " + Arrays.toString(intArray)); } return intArray; } }
如果我们编译并运行上述程序,则会产生以下结果 −
Input Array: [4, 6, 3, 2, 1, 9, 7] ================================================== Items compared: [ 4, 6 ] Items compared: [ 6, 3 ] Items compared: [ 6, 2 ] Items compared: [ 6, 1 ] Items compared: [ 6, 9 ] Items compared: [ 9, 7 ] Iteration 1#: [4, 3, 2, 1, 6, 7, 9] Items compared: [ 4, 3 ] Items compared: [ 4, 2 ] Items compared: [ 4, 1 ] Items compared: [ 4, 6 ] Items compared: [ 6, 7 ] Iteration 2#: [3, 2, 1, 4, 6, 7, 9] Items compared: [ 3, 2 ] Items compared: [ 3, 1 ] Items compared: [ 3, 4 ] Items compared: [ 4, 6 ] Iteration 3#: [2, 1, 3, 4, 6, 7, 9] Items compared: [ 2, 1 ] Items compared: [ 2, 3 ] Items compared: [ 3, 4 ] Iteration 4#: [1, 2, 3, 4, 6, 7, 9] Items compared: [ 1, 2 ] Items compared: [ 2, 3 ] Output Array: [1, 2, 3, 4, 6, 7, 9] ==================================================