经典排序之选择、冒泡、插入排序与系统排序的用时比较（Java）

比眉伴天荒 2022-06-16 10:45 141阅读 0赞

import java.util.Arrays;
    import java.util.Random;
    
    public class Demo {
    	public static void main(String[] args) {
    		int[] array = new int[20000];
    		Random r = new Random();
    		int rand;
    		for(int i=0; i<array.length; i++){
    			rand = r.nextInt();
    			array[i] = rand;
    		}
    		int[] array1 = Arrays.copyOf(array, array.length);
    		int[] array2 = Arrays.copyOf(array, array.length);
    		int[] array3 = Arrays.copyOf(array, array.length);
    		long time1 = System.currentTimeMillis();
    		selectionSort(array);
    		long time2 = System.currentTimeMillis();
    		bubbleSort(array1);
    		long time3 = System.currentTimeMillis();
    		insertSort(array2);
    		long time4 = System.currentTimeMillis();
    		Arrays.sort(array3);
    		long time5 = System.currentTimeMillis();
    		System.out.println("选择排序用时：" + (time2-time1));
    		System.out.println("冒泡排序用时：" + (time3-time2));
    		System.out.println("插入排序用时：" + (time4-time3));
    		System.out.println("系统排序用时：" + (time5-time4));
    	}
    	/** 选择排序 */
    	public static void selectionSort(int[] array) {
    		for(int i=0; i<array.length-1; i++){
    			for(int j=i+1; j<array.length; j++){
    				if(array[i] > array[j]){
    					int temp = array[i];
    					array[i] = array[j];
    					array[j] = temp;
    				}
    			}
    		}
    	}
    	/** 冒泡排序 */
    	public static void bubbleSort(int[] array) {
    		for(int i=0; i<array.length-1; i++){
    			for(int j=0; j<array.length-1; j++){
    				if(array[j] > array[j+1]){
    					int temp = array[j];
    					array[j] = array[j+1];
    					array[j+1] = temp;
    				}
    			}
    		}
    	}
    	/** 插入排序  */
    	public static void insertSort(int[] array) {
    		int i, j, temp;
    		for(i=1; i<array.length; i++){
    			temp = array[i];
    			for(j=i-1; j>=0 && array[j]>temp; j--){
    				array[j+1] = array[j];
    			}
    			array[j+1] = temp;
    		}
    	}
    }

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[0_1325987507Z03Q.gif]: /images/20220616/cd00ced606dc4449bafa513c352a26a0.png