我写的杨辉三角生成算法，请大家评价一下，有没有不足或更好的算法

westuser 2009-05-05 04:06:00

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是否会造成内存泄漏？
是否有更优的算法？我看到一个是先把所有的1先赋值，再填充其它项，循环两次我觉得不太好。



unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, ExtCtrls;



type

  TForm1 = class(TForm)

    Memo1: TMemo;

    Panel1: TPanel;

    LabeledEdit1: TLabeledEdit;

    Button1: TButton;

    Button2: TButton;

    procedure Button2Click(Sender: TObject);

    procedure Button1Click(Sender: TObject);

  private

    yh:array of array of Integer;

    procedure yhTriangle(row:Integer);

    { Private declarations }

  public

    { Public declarations }

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



procedure TForm1.Button1Click(Sender: TObject);

var

    s:TStrings;

    ss:string;

    r,I,J: Integer;

begin

    try

        r:=StrToInt(LabeledEdit1.Text);

    except

        r:=0;

        ShowMessage('只能输入数字');

        LabeledEdit1.Clear;

        LabeledEdit1.SetFocus;

    end;

    yhTriangle(r);

    s:=TStringList.Create;

    for I := 0 to r - 1 do

    begin

        ss:='';

        for J := Low(yh[i]) to High(yh[i]) do

            ss:=ss+IntToStr(yh[i][j])+' ';

        s.Add(Trim(ss));

    end;

    Memo1.Lines:=s;

    s.Free;

end;



procedure TForm1.Button2Click(Sender: TObject);

begin

    Close;

end;



procedure TForm1.yhTriangle(row:Integer);

var

    i: Integer;

    j: Integer;

begin

    //开辟空间

    SetLength(yh,row);

    for i:= Low(yh) to High(yh) do

    begin

        SetLength(yh[i],i+1);

    end;

    //填充

    for i := Low(yh) to High(yh) do

        for j := Low(yh[i]) to High(yh[i]) do

        begin

            if (j=Low(yh[i])) or (i=j) then

                yh[i][j]:=1

            else

                yh[i][j]:=yh[i-1][j-1]+yh[i-1][j];

        end;

end;



end.

...全文

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ztdou 2009-05-07

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全是些没用的评论！

yuxingleo 2009-05-07

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Console.WriteLine(" 1\n");
Console.WriteLine(" 1 1\n");
Console.WriteLine(" 1 2 1\n");
Console.WriteLine(" 1 3 3 1\n");
Console.WriteLine(" 1 4 6 4 1\n");
Console.WriteLine(" 1 5 10 10 5 1\n");
Console.WriteLine(" ………………………………");

love1901 2009-05-07

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顶一下

wangzhiwei0823 2009-05-07

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写复杂了

a61032707 2009-05-07

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顶～

wangkongxinglang 2009-05-07

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运行调试调试不就知道了

lidald 2009-05-07

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你累不？

zrpxxx 2009-05-07

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wangjun1990521 2009-05-07

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你的编程风格不啥好啊

KevinLaw 2009-05-07

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好复杂，支持一下

jm8542 2009-05-06

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这个不会

deepsky725 2009-05-06

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问题很尖锐啊

测试菜鸟 2009-05-06

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mark

gui911gui 2009-05-06

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看起来是有点复杂了！

cammy168 2009-05-06

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路过～顶一顶

vs_kobe 2009-05-06

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还OK吧.....

bber01 2009-05-06

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<html>

<head>

	<title>Untitled</title>

	<SCRIPT language="JavaScript">

		/*

		Example 1:

			in: 1

			out: 1 1

		Example 2:

			in: 1 1

			out: 1 2 1

		Example 3:

			in: 1 2 1

			out: 1 3 3 1

		...

		*/

		function nextLine (thisLine)

		{

			var inArr = thisLine;

			var outArr = new Array ();

			for (var i = 0; i <= inArr.length; i++)

			{

				if (i == 0 || i == inArr.length)

				{

					outArr[i] = 1;

				}

				else

				{

					outArr[i] = inArr[i - 1] + inArr[i];

				}

			}

			return outArr;

		}

		

		/*

		1

		1 1

		1 2 1

		1 3 3 1

		1 4 6 4 1

		...

		*/

		

		function yhTriangle (n)

		{

			var Triangle = new Array ();

			Triangle[0] = new Array ();

			Triangle[0][0] = 1;

			//alert (Triangle[0][0]);

			for (var i = 1; i < n; i++)

			{

				Triangle[i] = nextLine (Triangle[i - 1]);

			}

			return printArr (Triangle);

		}

		

		function printArr (arr)

		{

			var str = '';

			for (var i = 0; i < arr.length; i++)

			{

				for (var j = 0; j < arr[i].length; j++)

				{

					str += arr[i][j] + ' ';

				}

				str += '\n';

			}

			return (str);

		}

	</SCRIPT>

</head>



<body>

	<label>lines:</label>

	<input type="Text" id="txtN" name="txtN" value="15">	

	<input type="submit" id="ud" name="ud" value="calculate" onclick="document.getElementById ('outTxa').value = yhTriangle (document.getElementById('txtN').value);">

	<br>

	<textarea id="outTxa" name="outTxa" style="width:100%; height:100%"></textarea>

</body>

</html>

jadeluo 2009-05-06

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把判断可以省略掉:



procedure TForm1.yhTriangle(row: Integer);

var

  i, j: Integer;

begin

  SetLength(yh, row);

  for i := 0 to row - 1 do

  begin

    SetLength(yh[i], i + 1);

    yh[i][0] := 1;

    yh[i][i] := 1;

    for j := 1 to i - 1 do

      yh[i][j] := yh[i-1][j-1] + yh[i-1][j];

  end;

end;