学步园

代码说明：在123456789或987654321中插入+-*/四则符号来算出一个固定的值。asc为true时是123456789，反之为987654321。

123456789算100，C#下时间为15秒，VBA下为56秒，快了3/4。

版权说明：本文来自狼版http://blog.csdn.net/northwolves/archive/2009/11/20/4841068.aspx一文，试着用C#实现了一下。初学C#，如果哪边有什么不对或可以优化，请大家指点。

static void GetAllResult(int result, Boolean asc)<br /> {<br /> int temp=0,num=0;<br /> string[] x = new string[9];<br /> string[] op = new string[5]{"+","-","*","/",""};<br /> string outResult;<br /> StringBuilder sb = new StringBuilder();<br /> Stopwatch sw = new Stopwatch();<br /> sw.Start();<br /> Console.WriteLine("运算中，请稍候......");<br /> for (int i = 0; i <= Math.Pow(5,8); i++)<br /> {<br /> temp = i;<br /> x[0] = (asc ? 1 : 9).ToString();<br /> for (int j = 1; j <= 8; j++)<br /> {<br /> x[j] = op[temp % 5] + (asc?j + 1: 9 - j).ToString();<br /> temp=temp /5;<br /> }<br /> outResult = string.Join("",x);<br /> if ((new DataTable().Compute(outResult ,null)).ToString() == result.ToString())<br /> {<br /> num++;<br /> sb.Append("解 " + num + ":/t" + outResult + "=" + result + "/n");<br /> }<br /> }<br /> Console.WriteLine(sb.ToString());<br /> sw.Stop();<br /> Console.WriteLine(sw.Elapsed.ToString());<br /> Console.ReadLine();<br /> }<br /> static void Main(string[] args)<br /> {<br /> GetAllResult(100,true);<br /> }