jonson

1。100的阶乘的程序：

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *<p>计算 100！ 的值</p>
 * @author Administrator
 */
public class MultiValue {

    private static int[] getArrayFromInt(int value) {
        String temp = String.valueOf(value);
        byte[] a = temp.getBytes();
        int[] result = new int[a.length];
        for(int i = 0;i < a.length;i++)
        {
            result[i] = Integer.parseInt(Character.toString((char)a[i]));
        }
        return result;
    }
    
    public static void main(String[] args)
    {
        long start = System.currentTimeMillis();
        int[] result = caculator(100);
        for(int i = 0;i<result.length;i++)
        {
            System.out.print(result[i]);
        }
        long end = System.currentTimeMillis();
        System.out.println();
        System.out.println("time usage:"+(end-start));
    }
    
   private class IllegalParamException extends Exception
    {
        public IllegalParamException(){}
        public IllegalParamException(String message){
            super(message);
        }
    }
    
  static public int[] caculator(int v) {
        //System.out.println(Arrays.toString(a));
        if(v < 0)
        {
            return new int[]{1};
            //return {'1'};
        }else if(v ==0)
        {
            return new int[]{1};
        }else
        {
            return process(caculator(v-1),v);
        }
    }
    
    //数组的结构为：[1,2,3,4] x 99,value <=100
    //write test
   static private int[] process(int[] caculator, int value) {
        //(n-1)!  x  n  = n!   1234 x 99 = 
        int[] aValue = getArrayFromInt(value);
        //临时数据存储单元
        int ten_temp = 0;
        int[][] temp1=new int[aValue.length][caculator.length+3];
        for(int i=0;i<aValue.length;i++)
        {
            for(int j=0;j<caculator.length;j++)
            {
                int tt = aValue[aValue.length-1-i]*caculator[caculator.length-1-j];
                temp1[i][caculator.length+2-i-j]=(tt+ ten_temp)%10 ;
                ten_temp = (tt+ten_temp) / 10;
            }
            temp1[i][2 - i] = ten_temp;
            ten_temp = 0;
        }
        
        ten_temp = 0;
        int[] result = new int[caculator.length+3];
        for(int i=0;i<caculator.length+3;i++)
        {
            int tttt =0;
            for(int j=0;j<temp1.length;j++)
            {
                tttt = tttt +temp1[j][caculator.length+2-i];
            }
            result[caculator.length+2-i] = (tttt + ten_temp)%10;
            ten_temp = (tttt + ten_temp) / 10;
        }
        
        return result;
    }
}

init:
deps-jar:
Compiling 1 source file to C:\Documents and Settings\Administrator\My Documents\NetBeansProjects\HelloWorldApp\build\classes
compile-single:
run-single:
0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000093326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000
time usage:63
BUILD SUCCESSFUL (total time: 4 seconds)


该实现是利用数组来保存临时值。

时间：63 微秒

3.SELECT PCLASS, PSCORE from (select PCLASS,max(PSCORE) as PSCORE ,count(PSCORE) count from class_score
group by PCLASS) Temp where count>1

难道大家都是超级高手！！都不需要练手？还是觉得题目太简单！
其实在工作之余 做做小题目练练手，我觉得还不错阿。