2.1.25

import edu.princeton.cs.algs4.*;

public class Insertion
{
    public static void sort(Comparable[] a)
    {
        //冒泡前先保存于temp中,中间交换直接进行覆盖(所以要保存到temp中)操作,直到条件不满足时再用temp对该元素进行覆盖,从而没有交换
        int N = a.length;
        Comparable temp;
        for(int i = 1; i < N; i++)
        {
            temp = a[i];
            int j;
            for(j = i; j > 0 && less(temp, a[j-1]); j--)//此时应该比较temp和前一个元素j-1,而不是比较j和j-1
                a[j] = a[j-1];//覆盖操作
            a[j] = temp;
        }
    }
    
    private static boolean less(Comparable v, Comparable w)
    {
        return v.compareTo(w) < 0;
    }
    
    private static void show(Comparable[] a)
    {
        for(int i = 0; i < a.length; i++)
            StdOut.print(a[i] + " ");
        StdOut.println();
    }
    
    public static boolean isSorted(Comparable[] a)
    {
        for(int i = 1; i < a.length; i++)
            if(less(a[i], a[i-1])) return false;
        return true;
    }
    
    public static void main(String[] args)
    {
        String[] a = In.readStrings();//CTRL + d
        sort(a);
        assert isSorted(a);
        show(a);
    }
}