排序算法——插入排序(java實作)

1、算法實作:

import java.util.Arrays;

public class MySort {
    // 數組長度
    private final static int length = 50000;
    private static int[] array = new int[length];
    public static void main(String[] args) {
        // 初始化一個随機數組
        getArray();
        // 記錄排序所用時間
        TimeCost timeCost = new TimeCost();
        // 插入排序
        sort_insert();
        long cost = timeCost.elapsedTime();
        System.out.println(cost);
        System.out.println(Arrays.toString(array));
    }


    /**
     * 插入排序
     */
    private static void sort_insert(){
        for (int i = 1; i < length; i++) {
            for (int j = i-1; j >= 0; j--) {
                if (array[j+1] < array[j]){
                    int temp = array[j+1];
                    array[j+1] =  array[j];
                    array[j] = temp;
                }
            }
        }
    }


    /**
     * 初始化一個随機數組
     */
    private static void getArray(){
        int i = 0;
        while (i < length){
            array[i] = (int) (length * Math.random());
            i++;
        }
    }

    /**
     * 記錄時間開銷
     */
    static class TimeCost{
        private final long start;
        TimeCost(){
            start = System.currentTimeMillis();
        }
        private long elapsedTime(){
            long now = System.currentTimeMillis();
            return (now - start) ;
        }
    }
}